WARNING................. that upload site pops a dating service advert........... you may not want that to happen depending on where you are?

This might help:

http://www.virustotal.com/analisis/0...c57a8ab00e145c

http://www.virustotal.com/analisis/b...cda3fe708b1bd7

But AV utilities tend to do that with several security analysis tools, and some even complain if they find UPX

The author won't release the source so it boils down to whether or not you trust compiled binaries from him.