I can't tell. When I leave a place, and go to the Start A Game screen, I find new music on the list, so I enable it, but when I start a server, the chat keeps saying that it's deleted the music!
That may be because it's stereo, not mono music:
1. Get Audacity. (i think its free)
2. Open a .ogg music file from C:.blockland/add-ons/music/.
3. Check to see if there is 2 music tracks.
4. Click on the tittle of the grouped music track and select "Split Stereo Track".
5. Press X on one of the now ungrouped music tracks.
6. Click on the tittle of the remaining music track, and click "Mono" if it is not already selected.
7. Click file and then click "Export as Ogg Vorbis"
8. Save to C:.blockland/add-ons/music/.
9. Enable it and test.