I think I got it, will post here so others can make use of this:
UPDATE `dbtech_downloads_comments` SET userid = 1522 WHERE fileid = 30 AND comid = 3
So basically, search the username in your vbulletin admin and you will see it's userid #, then on the files download page you will see the fileid in the url and lastely the comid is the number of the comment in order it was posted. Hard for me to explain but makes sense in my head! LOL