No sound in Audacity, but got sound everywhere else

[Charles Kanavle]

My Dell E1705 runs Kubuntu 8.04 just fine... until I try to edit 
sound with Audacity. I come over from Adobe Audition, but have to 
keep returning to it because when I try to play the timeline on an 
audio track Audacity, I get the travelling cursor and visual 
indication of play mode, but no actual sound in the speaker. Other 
programs produce sound just fine during the same session.
Has any one else had a similar probrem?
Thanks all...
Charles