I believe what's happening is that RLinkVc has somehow been messed up, so when creating a new e-mail from a record and attaching a PDF, it's creating a new RLinkVc with a number which already exists in RLinkVc, and therefore attaching both the original file with that link number as well as the new file. Let me know if your export/import works and doesn't lose any of the old links, if that's possible to find out.