No audible mail notification in T'bird after upgrade to 8.04

[Rick Knight]

Prior to upgrading to 8.04, my audible email notifications from 
Thunderbird worked fine. After the upgrade, none of the KDE sound files 
work in Thunderbird. I have discovered that the Alsa sound files in 
/usr/share/sounds/alsa/  do work. How can I get the KDE sounds to work?

Thanks,
Rick