crawler_nt's point about naming is interesting. Also, do your audio files have id3 tags? Having both file names & id3 tags will help them to be found. The more id3 tag info the better. I always try to tag using "both" ID3v2.x & ID3v1.1
Tags will help files show up in search results because with more info, there's a greater chance a part of that info will tie in with someone's search.

BTW your bug report looks healthy to me.