I cannot create a simple website from template in the webmatrix.

i was about to create a simple website from webmatrix to test some new code. but it showed a message that an error caused Microsoft Webmatrix shut down. the message is here:

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An error caused WebMatrix to shut down.

Error Message:

 The calling thread connot access this object because a different thread owns it.

Error Log File:

 C:\Users\TWINLA~1\AppData\Local\Temp\WebMatrix.exe.log

Click 'Yes' to restart the program.

Click 'No' to visit the online forums for more information.

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Error log file's contain:
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9/23/2012 2:53:26 PM
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System.InvalidOperationException: The calling thread cannot access this object because a different thread owns it.
   at System.Windows.Threading.Dispatcher.VerifyAccess()
   at System.Windows.DependencyObject.SetValue(DependencyProperty dp, Object value)
   at Microsoft.WebMatrix.Gallery.TemplateSelectorControl.EndProgress()
   at Microsoft.WebMatrix.Gallery.TemplateSelectorControl.TemplateInstaller.OnError(Exception e)
   at Microsoft.WebMatrix.Gallery.TemplateSelectorControl.TemplateInstaller.OnInstallManager_InstallCompleted(Object sender, EventArgs e)
   at Microsoft.Web.PlatformInstaller.InstallManager.SendProductInstallChainCompleted()
   at Microsoft.Web.PlatformInstaller.InstallManager.StartInstalling()
   at Microsoft.Web.PlatformInstaller.InstallManager.StartDownloadAndInstall(Object unused)
   at System.Threading.QueueUserWorkItemCallback.WaitCallback_Context(Object state)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean ignoreSyncCtx)
   at System.Threading.QueueUserWorkItemCallback.System.Threading.IThreadPoolWorkItem.ExecuteWorkItem()
   at System.Threading.ThreadPoolWorkQueue.Dispatch()
   at System.Threading._ThreadPoolWaitCallback.PerformWaitCallback()

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i install webmatrix 1 and microsoft web plarform installer 4.0