Music Player Daemon

I'm not able to get MPD to play a .zip file full of spc and vgm files. Using GMPC, I'm able to peruse the .zip and view/add the tracks to the play queue, but they return a "problem decoding" error when playing. I've tested the files individually; they play uncompressed. I've also tested other file formats within zip files (for sanity) and they play fine too.

Has anyone seen this behavior? Using MPD 0.17.3