Cannot load Gungame

[Cruma]

I followed the installation guide to the best of my ability but I get this in console when I type:
rcon es_load gungame51

Can't load addon (gungame51): No module named mp3lib

[Warren]

It looks like you didn't extract all of the files from the download, or they didn't end up in the right place. Some of them must have ended up in the right place because GunGame tried to load, but try extracting the whole thing again.