I am also having problems backing up my Wii games I've been using Rawdump (download available at everything4wii.com). It actually copies the Wii disc to your hard drive and then you can go into ImgBurn to burn it. (Their website talks you thru it step by step.)
That being said, the problem I am now having is that everything went smoothly with the first two games I backed up but now I end up with a verified disc that won't play or else it gets into the 90%s on veryfing and I get a "Failed to read sector ####" or something similar. This is happening with three different discs. [Thought it safer, and cheaper, to back discs up (grandsons with helpful little fingers ) before something gets ruined.]
Any ideas why the burned and verified disc won't play? I've tried DVD-R and DVD+R. Doesn't seem to make a difference. I'm running out of patience and discs!!