If it starts with: "Exception (DSI) occured" and you see a black screen with some random numbers, it is an (Here it comes!) DSI error. This is basically just an error message when the Wii tries to do something, but it fails. Many times this happens because a channel or an cIOS doesn't work properly. As it happens not just with a channel, it is probably cIOS 249/250 or the HBC's IOS. Would you mind psting a syscheck?