It cant be the same error... That class has been removed, can you please post your MediaPortal.log, error.log and MusicVids.log
UPDATE: I have installed the latest SVN version and tested the latest Maintenance Release, I have no issues with this setup. Please ensure you have downloaded the latest version, as you may have got the older one if you had downloaded it before the MP repository had updated the listing.
Failing that, let me see your logs.