Okay, so I am a riivolution user and common5_en.pac doesn't work at all. I've put it in: SD Card/private/wii/app/RSBP/pf/system. I have followed all the tutorials but it never works, PLEASE HELP!!!
Wrong directory; put it in SD Card Root->ssbb->projectm->system instead; that's the default Riivolution setup; also, you still need the .gct file, but under a different name and stuff, to get any Riivolution hacks to work.
But yeah, Donald is right about removing the "_en" part.