[gh0sth@cker]

Could be related to the read/write speed and the condition of the original media. You say that when you use the default game profile it sometimes works - when you use this profile the subchannel boxes will be ticked and this often will reduce the read speed which may be helping.
Try to identify one of the problematic disks, clean in with a soft cloth (from inside out, not circularly), then read it at a slow speed - mount it to see if it works. If so, then do a slow write.

Experiment a little with some vaiables to see if you can identify the problem