Go to C:\program files\common files\ulead systems\mpeg
Delete any files that hve mp3 in the name, like ulmp3enc.ax_ and others.
You should be then able to put MP3 files into your projects.
I also worked out that if you try and put MP3 files into your project, without deleting the above files, and they won't work. Open the mp3 file with audio filter and voila! the mp3 file will now play in your project.
I hope that helps some poor unfortunate users out there..
