If all you're seeing in Preferences > File Converters is MP3 and WAV you've got a bad install. Try installing the portable version just to confirm and then either stay with that, or uninstall, download, and reinstall the non-portable version.
Or you can simply try patching your current version to 3.1, which is pretty damn stable. The worst that could happen is that you'd see no change. See my sig for patch versions.