Can I verify the file paths of Referenced Files ?

I've built a little system that sends email attachments from Filemaker (using Xmail the AppleScripting addition) I'm concerned that after my users upload files to the system, they may delete the file reference or rename the file, in which case, the referenced file's path will be inconsistent with where Filemaker thinks the file is..

so, when the system tries to email the attachment, the email will fail (or at least the attachment will fail).

Is there a way I can verify the file paths from Filemaker before the system tries to act on them ?

or... could someone recommend another plan of action ? I currently have people maintaining the files they upload to the filemaker systrem in a shared folder on the machine running the copy of Filemaker Server that is hosting the database. So I guess,

worst case scenario-- I guess I could just put a Readme file in the directory they are maintaining the files... saying "please do not delete or rename files or folders from this Shared Folder!!" but this is a pretty crappy way to go about things I think.

thanks