Hacking Black screen with several Games

[LinkinParkmetre]

Hello, i have this strange problem
When i load games with Wiiflow, some are encountering problems (i couldn't test them all so far)

With New Super Mario Bros, i can access the menu, and then, when i select a game, i get a black screen
With Super Mario Galaxy 2, i can also access the menu, but when i want to start a game, also a black screen
With No More Heroes 2, i can only play the first sequence of the game and then there's an infinite load

But with Metroid Other M i tried today, i could play for several hours

Any clue?

Thanks a lot