I've yet to see a forum where MP3's had to be zipped first, though... Are you SURE the software can't handle it, or is this just for uploading and the forum software unzips it at your end?
You are right Diki. It was just a setting that I needed to dig up and change. I will try an MP3 of a song I recorded with Colin Haye from Men At Work and Guy McDonough from Australian Crawl years ago to see if it is working ( Written by Guy and myself ) . And it looks like it is.