It's entirely possible that you're missing IOS files for these channels.
I'd try to download some IOS wads somewhere and install them, or get a game that has a bunch of them (Like Brawl)
You don't need a new System Menu (3.1, 3.2, etc.) but you will need the IOS files. (IOS30, IOS35). Of course, I don't know which ones you'd need necessarily. You could try running the SD Title Lister (No link sorry) to find out what IOS version you have on your Wii... Then post the results here.