Airplayne uses another media player internally to handle the actual playing of audio files. You can switch between available players on the Playback tab of the Options dialog.
BASS Audio Library, including most of the available plugins, is included with Airplayne and should work out of the box.
When using Windows Media Player, you can add support for additional audio file formats by installing one or both of
VLC Media Player supports most (if not all) audio file formats out of the box. Using VLC in Airplayne requires VLC to be installed including the ActiveX component:
Download the VLC installer at videolan.org.