JCPSP or JAVA error ? Help !

[JaCk IN Core]

I have problem when i try to play some new game of psp
JCPSP is far improve than ever I know
Even, japanese font are getting clearer than before.

I really thanks and grateful to creator
but I have some problem
It seem JAVA crash. when i try to select ISO from UMD

I have no idea why ? some game do work properly, but some do crash even without running them

What shall I do ?
my jcpsp (x86) 2437

Can somebody please help me ? I wish to get to play the game I longed wait for.