Forbidden memories: anti mod chip code

Hi everybody,
we use a ps-x-change cd (ver 2) to play PAL games on a US PSone, which works fine normally.
The game "Yu-Gi-Oh: Forbidden memories" (we tried the original game, not a copy) seems to be protected. Can we by-pass the protection with a mod chip code and, if yes, can sb help us dummies with the right one?
Thanks a lot!