Unfortunately, we are not able to reproduce the problem. Can you please follow the steps below and let us know if the problem still persists? Be sure to back up your project and database:
1. Remove all the .master files from the App_Master folder except the Dummy.master file and put them in a temporary directory.
2. Restart IIS and run the application.
3. Move back the files back to App_Master folder.
4. Restart IIS once again.
If the problem still persists, please send us your project along with the database to see what we can do about it. Your problem occurs in the module initialization which in the next version will use different implementation and the problem should not exist any more.
Hope this helps.