Did you use FileMaker Pro to upload them to the server? What OS are you using? Remember that using the Finder in Mac OS X to drag files there will mess up permissions. Permissions are not an issues on Windows servers. But if you have a Mac, what are the POSIX permissions of the file? Is it possible that the drive is locked? Make sure that the fmserver account has read/write access and not whatever your user is.
Thanks, I got it sorted out!
All the best,