Hello. I'm trying to upload a specific song. I have Windows Media, so it won't let me upload it. What can I do? ] Can I somehow change the file so that it's .au or .wav??? Please help

You need to have a midi player to be able to hear those files

Uploading has nothing to do with filetype unless you are trying to upload an mp3 which is not allowed by Bravenet in the hosting service. Just upload a wav or midi file like you would any other file in either the file manager, the java ftp applet, or whatever ftp program you use.