Ok, I've tested the archive with winrar and everything is fine. I've verified the par2 files. I've also checked the rar's and par's with sfv and everything checked out ok. I've also extracted the file from the archive and it went just fine. I'm assuming something happened during the upload or on the server side so it should be an easy fix to just re-upload the 4 corrupted parts if I understand correctly.

Should I give them a different name so they don't get thrown into the same collection, or is it ok if they have the same title?