2 players freezes SSE and boss battles

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The one problem I've had with the homer skin by mariodk is when playing in the SSE. But then I realized it actually works in SSE its just that some strange reason it freezes when playing with 2 players. But with 1 player in SSE it works flawlessly without any glitches or freezing, even with non-hacked brawl characters such as fox and sonic it still freezes with 2 players. This happens the same with Co-op boss battles :P

Can someone tell me why is this happening and what did I do wrong?