I just recently transferred all my Wii stuff to my Wii U, and when I tried to play a N64 game it, said, "This channel can not be launched on this Wii console." How do I transfer Nintendo 64 games onto my Wii u?
This thread on the Nintendo help forums suggests that it may be possible if you delete the game and re-download it. It seems that some users have had success in playing N64 games in Wii mode, so I would give it a shot. I believe the problem may lie in the fact that the software is designed to only work with a specific Wii (to prevent pirating), and that code did not update correctly when you transferred the data to your Wii U.
Make sure you have a classic controller though, as GC controllers will not work with the Wii U.
Sadly, transferred N64 games don't work on the Wii U when it is in Wii Mode. I would recommend buying the games again.