Scenario
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 - Add and save a new file using the flex/flash file uploader in the document library
 - Edit the record -> delete the file -> upload a new file -> save record
 - FarCry removes the original file, but never saves the new file you uploaded

When you go back in to edit the record, it seems that database is displaying your original file attached to the record. Try to preview it and you get a 404 as the actual file was successfully deleted (but the new file hasn't been saved in the database or file system)

Also if you add and save a new file, then edit the record and upload a new file (without deleting the old one) nothing happens. The database isn't updated with the new file and the file isn't uploaded to the file system. I imagine if a file is attached to a record, the file uploader (swf) shouldn't appear until such time that you "delete" the original file.