I think that happens when you save with StarForge, and then with Xtra-Editor. (Not exactly sure)
All you need to do is open the map with WinMPQ, then click Add and add your music files into the map, then a pop up box will show up then simply type staredit\wav\ and your file will turn out like staredit\wav\music.wav (or whatever the name of you wav file is)
Then just save and it should work fine.