It's the error within HBB?
Assuming it is not, and the error is a black screen full of white numbers and such, you just got a Wii code dump.
Try setting setting_disusb in your settings.xml to "1." If it doesn't exist, add this:
setting_disusb="1"
This will prevent the HBB to mount usb and will prevent in some cases also some crashes.
Also be sure to use the secondary server, the primary is down. (Setting_server="1")