This is the mv_music.vp bug rearing its head yet again. Taylor has released a build recently which may solve the problem. If it doesn't though try this.
If you've got mv_music.vp simply rename this to mv_music.vpdiabled.
If you've got the zPack (which incorporates mv_music.vp) you will also get this crash and unlike those using mv_music they can't just simply remove the offending vp file.
The fix is relatively simple though. Download
this file, Unrar and install the resulting music.tbl file to Freespace2\data\tables\
When the next zPack is released you should remember to delete it though.