First, who did you buy the new problem-gct from?
Have you tried swapping the memory with your working gct? Also, check to see that no pins are bent on either the cf port on the motherboard, or the ide port. Just an idea (a dumb one probably).
Another thing to think about...are the versions of your gct's the same?
I think it's your cf disk...you might try writing codeman's linux image to it if possible, just to see if that makes any difference.
Of course, make sure all the connections are solid, it might just be a loose wire.
Hope this helps,