.scd support was only added to vgmstream in r834. I assume that what is happening in r832 is that Winamp is playing the unsupported .scd as MPEG (as is its default behavior for unknown files) and you're totally bypassing vgmstream. Do you have confidence that your newer vgmstream install is working at all? Check the readme for necessary external dlls (and maybe copy them anew if you already had them, they may have changed).
Yeh it plays everything but the scds. Hmm it's a while back now, but I may have tagged them thinking it was a supported format, which actually broke them. Short of renaming each one to .mp3 there's no way to turn off individual extensions in vgmstream, is there?
Oh nvm, I think I'm still seeding that set so I can just unpack it again. Sorry for the thread :p