Android project failed to create apk suddenly!

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Android

Eclipse

Error generating final archive: Failed to create '/Volumes/Android/workspace/flipfree/bin/flipfree.apks': Input/output error

The application could run this morning. But my portable hard drive was accidentally pushed out, while the app was running. After I restarted the Eclipse and ran this project, the Error Log popped out this error, nothing appeared after then, even the emulator!

Here is the Exception Stark Track for the error above:

com.android.sdklib.build.ApkCreationException: Failed to create '/Volumes/Android/workspace/flipfree/bin/flipfree.apks': Input/output error
	at com.android.sdklib.build.ApkBuilder.checkOutputFile(ApkBuilder.java:912)
	at com.android.sdklib.build.ApkBuilder.init(ApkBuilder.java:437)
	at com.android.sdklib.build.ApkBuilder.<init>(ApkBuilder.java:422)
	at com.android.sdklib.build.ApkBuilder.<init>(ApkBuilder.java:362)
	at com.android.ide.eclipse.adt.internal.build.BuildHelper.finalPackage(BuildHelper.java:391)
	at com.android.ide.eclipse.adt.internal.build.BuildHelper.finalDebugPackage(BuildHelper.java:359)
	at com.android.ide.eclipse.adt.internal.build.builders.PostCompilerBuilder.build(PostCompilerBuilder.java:632)
	at org.eclipse.core.internal.events.BuildManager$2.run(BuildManager.java:734)
	at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
	at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:206)
	at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:328)
	at org.eclipse.core.internal.events.BuildManager.build(BuildManager.java:403)
	at org.eclipse.core.internal.resources.Project$1.run(Project.java:618)
	at org.eclipse.core.internal.resources.Workspace.run(Workspace.java:2313)
	at org.eclipse.core.internal.resources.Project.internalBuild(Project.java:597)
	at org.eclipse.core.internal.resources.Project.build(Project.java:124)
	at com.android.ide.eclipse.adt.internal.project.ProjectHelper.doFullIncrementalDebugBuild(ProjectHelper.java:1143)
	at com.android.ide.eclipse.adt.internal.launch.LaunchConfigDelegate.launch(LaunchConfigDelegate.java:155)
	at org.eclipse.debug.internal.core.LaunchConfiguration.launch(LaunchConfiguration.java:885)
	at org.eclipse.debug.internal.core.LaunchConfiguration.launch(LaunchConfiguration.java:739)
	at org.eclipse.debug.internal.ui.DebugUIPlugin.buildAndLaunch(DebugUIPlugin.java:1039)
	at org.eclipse.debug.internal.ui.DebugUIPlugin$8.run(DebugUIPlugin.java:1256)
	at org.eclipse.core.internal.jobs.Worker.run(Worker.java:54)

And here is another strange thing, even though there is no error occurs in the all the files of the project, a little red cross appears in the root of the project. (Why there is no function for me to add a picture:( ) Please help, thanks!