Instructions
Turn on your Wii console and look for the Wii symbol in the lower left corner of the screen. Click on this symbol to go to the "Date Management" options.
Go to the "Wii Channels" option in "Date Management." Search for the defective downloaded Virtual game you want to delete. Click on the game, hit "Erase" and then confirm it.
Switch over to the Wii Shop Channel on your console. Go to the "Search by Game Title" option and look for the same video game's name. It should now say "Downloadable" instead of "Downloaded."
Select "Download" on the game. As long as the game remains on your shop account, you should be able to re-download it without paying any Wii points.