Why won't my Wii apps in the Homebrew Channel load up?

Hey I was wondering if anyone could help me out with this issue. My homebrew channel can't run most of my apps for some reason. I can run the snes emulator but I can't run the cios manager, wad manager or anything else, the screen just turns black. When I place a new wadmanager, cios instaler, etc. on the root of my SD card in the apps folder, the homebrew doesn't even read it. I recently upgraded to 4.3 U firmware a while back so I'm sure that's the problem.