What kind of audio file is it?
Are these problematic ones WMA files?
I'd recommend staying well away from WMA format. Such files are spammed on the network to either promote businesses or to try to curb file sharing by putting viruses and other dangerous website links inside the WMA files.

Also, some mp3 files that show up are not really mp3 files but have hidden .exe file extensions.

I'd recommend looking at these posts: 1. Virus thread: Typical virus spam file sizes - Make a note of them (click on blue link to see)

2. How to find music (& check the links Sleepless put in, they are not necessarily obvious links.)