Do you have a menu hack? That could be the cause of what's freezing...
I do, but I've had it since I first started and it's never caused an issue.
That happened to me when the hacks first started working. After a while I gave up and later tried again and it loaded. Does your Wii get really hot quickly, when mine gets hot it freezes like that, when the hacks are used.
It sometimes gets hot fast. I'm thinking of using a previous backup to try to get it to work.