BE CAREFUL WITH THIS. This is how I bricked my Wii.
I can at least tell you what NOT to do :/
I had two games that would not copy to the SD card- one which was installed via WAD Manager, and one that was a legal download through Nintendo. When I got fed up, I tried to Erase the WAD-installed one in Nintendo's data management, and it froze up during the deletion. I had to pull the plug.
After it booted back up, the wii would freeze if I went into data management. So I fired up WAD Manager and tried to delete it there. It deleted the title, then froze while deleting content. Again, I had to force power off.
I went back into WAD Manager, and tried to reinstall it. It locked again while installing content, and I had to force power off- and my Wii wouldn't boot afterwards.
The best thing to do is to probably back up, downgrade to 3.2, Format, and rehack. But if you find a fix, I'd love to know.