WTF!!!..can't switch to metal gear solid disk two..help!

[Pfunk]

okay, I've got a modded psx (of course) and when I play through on the original cd's, I can't continue on to disk two. I put in the second disk when prompted and all that loads is a blank black screen. Each disk will load fine individually, but I can't switch mid game like you have to to continue on. what the hell! I can't get to the second cd. how do I get around this??!!