Official disc will always read. So I assume these are backup copies, right? Are you loading through the Disc Channel? Install IOS38 Rev 14 (if you don't already have it) and cIOSCORP 3.2 and your problems should go away. CIOSCORP 3.3 is out but it fails at reading games that 3.2 suceeded in reading so stick with 3.2 until 3.4 is released.