USA Dreamcast + UK Sega Rally...problems, please help.

Hi,

i've got a USA Dreamcast + bootcd + UK Sega Rally. Obviously putting
in the Sega Rally GD comes up with unknown disk or whatever. Booting from utopia works fine and after inserting the Sega Rally disk,
all is OK, i.e. it recognises it and starts to load. Then the start screen comes up again (as if it's been reset) and I get back to the menu with unknown disk.

Any ideas??

Cheers.

Binny.