So you fixed your corrupted file system yes?
I had that trouble with my sd-card, not sure why. But I was able to access it from the maintenance mode, and after that the problem disappeared.
Boot the wii, hold + and - at the health screen, then push A while holding + and - down. Try to access the sd-card. Just a thought.
If you keep having trouble you should try to reinstall the system ios60, then your system menu- see if that fixes it.
Are you using preloader? or just bootmii?