??? for CameCube owners

alright.
i had everything unlocked in this game for XBox,
but then my XBox totally crapped out on me, so i
re-bought the game for GameCube... and so far,
i'm having a lot of problems (mostly involving
Konquest mode)

1. both the A button and the X button appear as
"A" during the excercises, but that's no big deal
once i figure out what they actually WANT me to press.
this also happens during arcade/versus if you pause
and look at the move list (i wouldn't have even noticed
that if my friends hadn't paused the game to look)

2. several combos in Konquest mode don't register,
even though i know i'm doing them correctly (for
example, Shang Tsung's A,A,A combo in snake stance).
there is no way to get around this which means i can
NEVER unlock Blaze and Mokap.

basically, i was wondering if anyone else out there
has this game on the GameCube platform AND is having
the same problems....or do i have a faulty disc???