Multiple autorun file in USB drive?

first of all I found 13 file(s) name autorun in my thumbdrive..
after scan it my AV found nothing dangerous..


if anyone can tell me what the heck is that ??
you can get the sample here or http://d.turboupload.com/d/1534536/autorun_virus.zip.html...
Use it at your own risk...
pa$$w0rd :psis.edu