Need to convert AIFF to MP3, but WMP wont recognise them. Soundwave says theres an error, but aiff play in QT?

I'm running Vista and I'm trying to convert AIFF files from a CD onto MP3, but I can't get Soundwave to do it. The AIFFs play fine in Quicktime, but won't play in WMP. What's going on?! I need them in MP3 format with a bitrate of at least 192. These are my own songs by the way, so there's no copy protection on the CD or anything. Arrrgh!