When a data file is inserted that cannot be recognized then an error message will always pop for every data file double clicked (in known and unknown file format)

I tried importing avi and Word files. The import was completed fine. However, after double clicking one these two files, an error message pops upi stating: Unhandled Event Loop Exception. Failed to execute runnable (java.lang.NUllPointer Exception). From that moment on, the message pops up everytime any file is viewed.