I’m not sure if this is the right place, but I am having a similar issue with my Western Digital hard drive on WiiMC. It was working up until the latest (1.1.2) version of WiiMC.
It crashes when I select ‘USB Media’ from the menu. There is a bunch of code, but I can’t easily read it on my CRT TV. I re-installed both HBC and IOS58 and checked that HBC was using 58 too.
EDIT: I’ve now also found this thread
http://www.wiimc.org/forum/viewtopic.php?f=4&t=1131
so I’ll try that. Sorry.