Thank you for your post.
If we could get a little more information from you:
Are you opening the file locally or is it being hosted by FileMaker Server?
-If hosted, did you upload the files with FileMaker Pro? (If not, could you?)
Have you tried opening the file locally from the Desktop?
-If the issue occurs on the Desktop, are you using a local Administrator Account, or a domain account?
-If it doesn't seem to be an Account Specific issue, you might run Recover on the .fp7 file and convert the recovered file into 14.
I look forward to your response!