I've been having a very similar problem, but despite these tips still can't get rockbox installed.
I'm running OS X 10.5.8, and the 4gig Fuze I just received is V02.03.33A
The firmware file which corresponds with this version number is fuzpa.bin, while the fuzea.bin apparently corresponds to a different (V01) version.
The issue I seem to be running into is that neither the automatic installer or the mkamsboot-mac manual installer is willing to work with the fuzpa.bin file. When I run mkamsboot-mac on this file I get this message:
"[ERR] OF File provided is Fuzev2 version 2.03.33, not for Fuzev1
[ERR] Could not load fuzpa.bin"
I have run through the same process with the fuzea.bin file and it worked like a charm. I loaded the new fuzea.bin file onto my player and nothing happened. I then renamed it fuzpa.bin and the player detected it and attempted to update its firmware. After a few seconds of this message the player turned off, the firmware was not installed, and the .bin file had been deleted.
Any idea what my problem could be?
thanks,
Chris