UNRAR PROBLEMS 360 issues

getting loads of errors when unraring 360 games ,MW3 and forza 4 were fine,but fifa 12 and a couple of others lego starwars clone wars and lego pirates of carabean ,wont unrar at all just get errors and slow my computer right down,and time left on unrar just keeps going up and up then it reports crc errors,but there cannot be as others have used them any help much appreciated

a lot of games get taken down for dmca especially using giganews.

I don't really understand what answers you're expecting. If the files won't unrar then they're corrupted. Use the sfv file to check them or the par file to try to repair them or else redownload them.