As the SQL query catched in the admin, i am thinking it has to be somewhere in the shop-side of things.
The only place i would suspect this to go wrong is indeed in newsletter_subscribe_filenames.php.
You allready said it's there, if it isn't corrupt then i wouldn't know why it would throw that error.
Maybe you should try re-uploading that file.
If that doesn't solve anything then i don't think the error is in subscribe mod, but i would probably remove the mod anyway and see if the shop would start running without an error again, or if you then possibly get a different error message.
Bookmarks