Why won't XMMS play .au files?

[Adam Funk <a24061@yahoo.com>]

I'm running the xmms 1.2.10-1 package.

$ apt-cache show xmms
...
 It's able to read and play:
  * Audio MPEG layer 1, 2, and 3 (with mpg123 plug-in),
  * WAV, RAW, AU (with internal wav plug-in and MikMod plug-in),
...

When I run XMMS the audio input plugin includes the following:
  MikMod Player 1.2.10 [libmikmod.so]
  Wave Player 1.2.10 [libwav.so]

But it will *not* play any of these files:

$ file *.au
foo1.au:       Sun/NeXT audio data: 16-bit linear PCM, stereo, 44100 Hz
foo.au:        Sun/NeXT audio data: 16-bit linear PCM, mono, 22050 Hz
vsound4090.au: Sun/NeXT audio data: 16-bit linear PCM, mono, 22050 Hz

Any idea why not?

-- 
Thanks,
Adam