diff --git a/user/src/com/google/gwt/junit/RunStyleSelenium.java b/user/src/com/google/gwt/junit/RunStyleSelenium.java
index afaa502..74e2332 100644
--- a/user/src/com/google/gwt/junit/RunStyleSelenium.java
+++ b/user/src/com/google/gwt/junit/RunStyleSelenium.java
@@ -16,12 +16,14 @@
 package com.google.gwt.junit;
 
 import com.google.gwt.core.ext.TreeLogger;
+import com.google.gwt.core.ext.UnableToCompleteException;
 
 import com.thoughtworks.selenium.DefaultSelenium;
 import com.thoughtworks.selenium.Selenium;
-import com.thoughtworks.selenium.SeleniumException;
 
+import java.util.ArrayList;
 import java.util.HashSet;
+import java.util.List;
 import java.util.Set;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
@@ -30,6 +32,13 @@
  * Runs via browsers managed by Selenium.
  */
 public class RunStyleSelenium extends RunStyle {
+
+  /**
+   * The maximum amount of time that a selenia can take to start in
+   * milliseconds. 10 minutes.
+   */
+  private static final int LAUNCH_TIMEOUT = 10 * 60 * 1000;
+
   /**
    * Wraps a Selenium instance.
    */
@@ -88,13 +97,184 @@
   }
 
   /**
+   * A {@link Thread} used to interact with {@link Selenium} instances. Selenium
+   * does not support execution of multiple methods at the same time, so its
+   * important to make sure that {@link SeleniumThread#isComplete()} returns
+   * true before calling more methods in {@link Selenium}.
+   */
+  class SeleniumThread extends Thread {
+
+    /**
+     * {@link RunStyleSelenium#lock} is sometimes active when calling
+     * {@link #isComplete()}, so we need a separate lock to avoid deadlock.
+     */
+    Object accessLock = new Object();
+
+    /**
+     * The exception thrown while running this thread, if any.
+     */
+    private Throwable exception;
+
+    /**
+     * True if the selenia has successfully completed the action. Protected by
+     * {@link #accessLock}.
+     */
+    private boolean isComplete;
+
+    private final SeleniumWrapper remote;
+
+    /**
+     * Construct a new {@link SeleniumThread}.
+     * 
+     * @param remote the {@link SeleniumWrapper} instance
+     */
+    public SeleniumThread(SeleniumWrapper remote) {
+      this.remote = remote;
+      setDaemon(true);
+    }
+
+    /**
+     * Get the {@link Throwable} caused by the action.
+     * 
+     * @return the exception if one occurred, null if none occurred
+     */
+    public Throwable getException() {
+      synchronized (accessLock) {
+        return exception;
+      }
+    }
+
+    public SeleniumWrapper getRemote() {
+      return remote;
+    }
+
+    public boolean isComplete() {
+      synchronized (accessLock) {
+        return isComplete;
+      }
+    }
+
+    protected void markComplete() {
+      synchronized (accessLock) {
+        isComplete = true;
+      }
+    }
+
+    protected void setException(Throwable e) {
+      synchronized (accessLock) {
+        this.exception = e;
+        isComplete = true;
+      }
+    }
+  }
+
+  /**
+   * <p>
+   * The {@link Thread} used to launch a module on a single Selenium target. We
+   * launch {@link Selenium} instances in a separate thread because
+   * {@link Selenium#start()} can hang if the browser cannot be opened
+   * successfully. Instead of blocking the test indefinitely, we use a separate
+   * thread and timeout if needed.
+   * </p>
+   * <p>
+   * We wait until {@link LaunchThread#isComplete()} returns <code>true</code>
+   * before starting the keep alive thread or creating a {@link StopThread}, so
+   * no other thread can be accessing {@link Selenium} at the same time.
+   * </p>
+   */
+  class LaunchThread extends SeleniumThread {
+
+    private final String moduleName;
+
+    /**
+     * Construct a new {@link LaunchThread}.
+     * 
+     * @param remote the remote {@link SeleniumWrapper} instance
+     * @param moduleName the module to load
+     */
+    public LaunchThread(SeleniumWrapper remote, String moduleName) {
+      super(remote);
+      this.moduleName = moduleName;
+    }
+
+    @Override
+    public void run() {
+      SeleniumWrapper remote = getRemote();
+      try {
+        String domain = "http://" + getLocalHostName() + ":" + shell.getPort()
+            + "/";
+        String url = shell.getModuleUrl(moduleName);
+
+        // Create the selenium instance and open the browser.
+        shell.getTopLogger().log(TreeLogger.TRACE,
+            "Starting with domain: " + domain + " Opening URL: " + url);
+        remote.createSelenium(domain);
+        remote.getSelenium().start();
+
+        // We set the speed to 1000ms as a workaround a bug where Selenium#open
+        // can hang.
+        remote.getSelenium().setSpeed("1000");
+        remote.getSelenium().open(url);
+        remote.getSelenium().setSpeed("0");
+
+        markComplete();
+      } catch (Throwable e) {
+        shell.getTopLogger().log(
+            TreeLogger.ERROR,
+            "Error launching browser via Selenium-RC at "
+                + remote.getSpecifier(), e);
+        setException(e);
+      }
+    }
+  }
+
+  /**
+   * <p>
+   * The {@link Thread} used to stop a selenium instance.
+   * </p>
+   * <p>
+   * We stop the keep alive thread before creating {@link StopThread}s, and we
+   * do not create {@link StopThread}s if a {@link LaunchThread} is still
+   * running for a {@link Selenium} instance, so no other thread can possible be
+   * accessing {@link Selenium} at the same time.
+   * </p>
+   */
+  class StopThread extends SeleniumThread {
+
+    public StopThread(SeleniumWrapper remote) {
+      super(remote);
+    }
+
+    @Override
+    public void run() {
+      SeleniumWrapper remote = getRemote();
+      try {
+        remote.getSelenium().stop();
+        markComplete();
+      } catch (Throwable e) {
+        shell.getTopLogger().log(TreeLogger.WARN,
+            "Error stopping selenium session at " + remote.getSpecifier(), e);
+        setException(e);
+      }
+    }
+  }
+
+  /**
    * The list of hosts that were interrupted. Protected by {@link #lock}.
    */
   private Set<String> interruptedHosts;
 
   /**
-   * Indicates that testing has stopped, and we no longer need to run keep
-   * alive checks. Protected by {@link #lock}.
+   * We keep a list of {@link LaunchThread} instances so that we know which
+   * selenia successfully started. Only selenia that have been successfully
+   * started should be stopped when the test is finished. Protected by
+   * {@link #lock};
+   */
+  private List<LaunchThread> launchThreads = new ArrayList<LaunchThread>();
+
+  /**
+   * Indicates that testing has stopped, and we no longer need to run keep alive
+   * checks. Protected by {@link #lock}.
    */
   private boolean stopped;
 
@@ -153,49 +333,61 @@
     Runtime.getRuntime().addShutdownHook(new Thread() {
       @Override
       public void run() {
+        List<StopThread> stopThreads = new ArrayList<StopThread>();
         synchronized (lock) {
           stopped = true;
-          for (SeleniumWrapper remote : remotes) {
-            if (remote.getSelenium() != null) {
-              try {
-                remote.getSelenium().stop();
-              } catch (SeleniumException se) {
-                shell.getTopLogger().log(TreeLogger.WARN,
-                    "Error stopping selenium session", se);
-              }
+          for (LaunchThread launchThread : launchThreads) {
+            // Closing selenium instances that have not successfully started
+            // results in an error on the selenium client. By doing this check,
+            // we are ensuring that no other calls to the remote instance are
+            // being done by another thread.
+            if (launchThread.isComplete()) {
+              StopThread stopThread = new StopThread(launchThread.getRemote());
+              stopThreads.add(stopThread);
+              stopThread.start();
             }
           }
         }
+
+        // Wait for all threads to stop.
+        try {
+          waitForThreadsToComplete(stopThreads, false, "stop", 500);
+        } catch (UnableToCompleteException e) {
+          // This should never happen.
+        }
       }
     });
-    start();
     return targets.length;
   }
 
   @Override
-  public void launchModule(String moduleName) {
-    // Get the localhost address.
-    String domain = "http://" + getLocalHostName() + ":" + shell.getPort()
-        + "/";
-
+  public void launchModule(String moduleName) throws UnableToCompleteException {
     // Startup all the selenia and point them at the module url.
+    for (SeleniumWrapper remote : remotes) {
+      LaunchThread thread = new LaunchThread(remote, moduleName);
+      synchronized (lock) {
+        launchThreads.add(thread);
+      }
+      thread.start();
+    }
+
+    // Wait for all selenium targets to start.
+    waitForThreadsToComplete(launchThreads, true, "start", 1000);
+
+    // Check if any threads have thrown an exception. We wait until all threads
+    // have had a change to start so that we don't shutdown while some threads
+    // are still starting.
     synchronized (lock) {
-      for (SeleniumWrapper remote : remotes) {
-        try {
-          String url = shell.getModuleUrl(moduleName);
-          shell.getTopLogger().log(TreeLogger.TRACE,
-              "Starting with domain: " + domain + " Opening URL: " + url);
-          remote.createSelenium(domain);
-          remote.getSelenium().start();
-          remote.getSelenium().open(url);
-        } catch (Exception e) {
-          shell.getTopLogger().log(
-              TreeLogger.ERROR,
-              "Error launching browser via Selenium-RC at "
-                  + remote.getSpecifier(), e);
+      for (LaunchThread thread : launchThreads) {
+        if (thread.getException() != null) {
+          // The thread has already logged the exception.
+          throw new UnableToCompleteException();
         }
       }
     }
+
+    // Start the keep alive thread.
+    start();
   }
 
   /**
@@ -221,6 +413,7 @@
           try {
             Thread.sleep(1000);
           } catch (InterruptedException ignored) {
+            break;
           }
         } while (doKeepAlives());
       }
@@ -250,8 +443,8 @@
             // If we ask for the title of the page while a new module is
             // loading, IE will throw a permission denied exception.
             String message = e.getMessage();
-            if (message != null
-                && message.toLowerCase().contains("permission denied")) {
+            if (message == null
+                || !message.toLowerCase().contains("permission denied")) {
               if (interruptedHosts == null) {
                 interruptedHosts = new HashSet<String>();
               }
@@ -263,4 +456,73 @@
       return interruptedHosts == null;
     }
   }
+
+  /**
+   * Get the display list of specifiers for threads that did not complete.
+   * 
+   * @param threads the list of threads
+   * @return a list of specifiers
+   */
+  private <T extends SeleniumThread> String getIncompleteSpecifierList(
+      List<T> threads) {
+    String list = "";
+    for (SeleniumThread thread : threads) {
+      if (!thread.isComplete()) {
+        list += "  " + thread.getRemote().getSpecifier() + "\n";
+      }
+    }
+    return list;
+  }
+
+  /**
+   * Iterate over a list of {@link SeleniumThread}s, waiting for them to finish.
+   * 
+   * @param <T> the thread type
+   * @param threads the list of threads
+   * @param fatalExceptions true to treat all exceptions as errors, false to
+   *          treat exceptions as warnings
+   * @param action the action being performed by the thread
+   * @param sleepTime the amount of time to sleep in milliseconds
+   * @throws UnableToCompleteException if the thread times out and
+   *           fatalExceptions is true
+   */
+  private <T extends SeleniumThread> void waitForThreadsToComplete(
+      List<T> threads, boolean fatalExceptions, String action, int sleepTime)
+      throws UnableToCompleteException {
+    boolean allComplete;
+    long endTime = System.currentTimeMillis() + LAUNCH_TIMEOUT;
+    do {
+      try {
+        Thread.sleep(sleepTime);
+      } catch (InterruptedException e) {
+        // This should not happen.
+        throw new UnableToCompleteException();
+      }
+
+      allComplete = true;
+      synchronized (lock) {
+        for (SeleniumThread thread : threads) {
+          if (!thread.isComplete()) {
+            allComplete = false;
+          }
+        }
+      }
+
+      // Check if we have timed out.
+      if (!allComplete && endTime < System.currentTimeMillis()) {
+        allComplete = true;
+        String message = "The following Selenium instances did not " + action
+            + " within " + LAUNCH_TIMEOUT + "ms:\n";
+        synchronized (lock) {
+          message += getIncompleteSpecifierList(threads);
+        }
+        if (fatalExceptions) {
+          shell.getTopLogger().log(TreeLogger.ERROR, message);
+          throw new UnableToCompleteException();
+        } else {
+          shell.getTopLogger().log(TreeLogger.WARN, message);
+        }
+      }
+    } while (!allComplete);
+  }
 }