Can't quite figure out whats going on with an 80020148 error I'm getting and would appreciate any suggestions!

As far as I can tell this error normally happens when the no-umd setting hasnt been activated in the recovery menu or when you need to upgrade your firmware. However I am running 4.01 M33 and have tried all 3 different 'no-umd' settings. Also it is just one game that gives this error (Crisis Core) whilst everything else works fine. To compound matters further it worked yesterday and I havn't done anything to it since then (i.e. no update, settings changes etc.). Don't know if its related at all but some of the Crisis Core's save games were corrupted so could this be a bad ISO?