If you want to play music on a music brick, it must be a mono audio file for it to work properly under the audio space positioning Torque uses, which is known as 3D sound. The only way to play stereo music through Blockland, is to use a client sided console command to play it directly to your client without any audio positioning, aka 2D sound. Meaning, only the client who puts in the console command can hear the 2D stereo music, unless you make a client sided add-on that everyone gets for a server so you can tell all of the clients what 2D music to play.
Edit: Oh and I almost forgot, if you try to enable stereo music on your server, Blockland rejects the music files because it only accepts mono music. So while you can play stereo music for your client, you can't put it on the server so everyone can download it. So if you want everyone to play the 2D music by their clients all at once, they have to manually download the stereo music files themselves.