Can't share audio in ALSA

[Gerardo]

I'm using Kubuntu 10.04 Lucid 64-bit and I'm having a problem that is 
driving me insane.  If I'm playing music on Amarok, or something in 
mplayer and another application uses the audio (i.e., KDE notification 
bell, flash video in firefox, etc...) the music stops.  The timer in 
Amarok/mplayer keeps running as if the song is still playing, but I 
can't get the audio back unless I stop playback and restart it again. 
Pausing and unpausing doesn't work.

The same thing works backwards.  If I'm watching a video in firefox and 
start Amarok, then the sound in firefox goes out and I have to reload 
the page for it to come back.  I didn't have any problems in Hardy.  It 
works fine on my kids computer.

I installed installed pulseaudio on this computer and later removed it 
and went back to ALSA.  I don't know if doing this fudged something.

Lou