I'm disappointed by the problems with the software - you had that too with yours - and the fact that it won't recognise wav files, wmv files etc. Also, the infrared is painfully slow. I know, I know, i got what i paid for!
to do it with free software go to
www.vnunet.com/downloads, or any other download site you may prefer, and type (Alt WAV MP3 WMA OGG Converter) in the searchbox.
it should appear. download it. even though i'm no expert, i found it very easy to convert wav to mp3.
goodluck whickerman.