new programmed filetype: Error when pre-tweaking file...

Hello,

I imported the filetype project sample from the sdk and have a problem in Studio. Studio seems to recognize the new filetype "plug-in" but each time I try to prepare the sample file, I get this error:

"Error when pre-tweaking file: The process cannot access the file 'Sample.text' because it is being used by another process."

Does someone have an idea where this problem comes from? The file is not open in any programm.

I restarted Studio but it didn't help. I restarted Windows 7 and it helped once, but just for the first preparation, the next ones generated the same error message and the second windows7 restart didn't help at all.

Thank you for your help

Sébastien