freeamp cannot open audio device, but aplay works fine

[Roland Kwee <roland@tesla.xs4all.nl>]

Strange problem: Freeamp (zinf) says "cannot open audio device",
but aplay (included with alsa-tools) plays soundfiles just fine.

I am running linux-2.6.0, Freeamp 2.1.1, aplay 0.9.6.

Unfortunately, aplay can play .wav but not .mp3/.ogg files, so I need freeamp. 
But freeamp (www.zinf.org) does not include any documentation. 
My /dev/dsp is present, but perhaps freeamp needs another device.

I would be grateful for information on configuring freeamp.

Regards, Roland Kwee