audacity doesn't work with usb sound card

[Johannes Wiedersich <johannes@physik.blm.tu-muenchen.de>]

Plugging my usb sound card, killing artsd, restarting alsa everything
seems to work fine (aplay, arecord), but when I start audacity, I get
the following error box:

/-----------
Error initioalizing audio
There was an error initializing the audio i/o layer.
You will not be able to play or record audio.

Error: Host error.
\-----------

audacity works fine with my laptop's built-in sound card as long as
there is no usb card attached.

Note that alsactl doesn't recognize the usb card. It would be nice, if I
could get the sound card working without having to kill artsd and
restarting alsa as root.

Debian etch; Terratec Phase 26 usb sound card

Thanks for any hints of how to fix this.

Johannes