I'm having this exact same issue. I'm fairly new to this stuff, and even though I've read the docs and have a reasonably good idea what romcenter is supposed to be doing with the FBAXXX pro DAT, it doesn't seem to be doing it. Fix doesn't seem to want to actually fix anything. The BAED3b disc, copied to my Xbox HDD, works great by itself - but I tried upgrading to FBAXXX 8-26, then I tried applying 'Patch 2' to make it act as an 8-02 Pro build. After I installed it on my Xbox and copied my roms over, I discovered that it doesn't like some of the very same roms it previously played without incident. I'm watching this thread with baited breath.