endless drumbeats after switching user in hardy

[Vitorio Okio]

This started happening a couple of months ago, it does not happen all the 
time but only once in a while, after I switch a user the default 
drumbeats gets stuck in an endless loop. The only way out of it is to 
reboot. Nothing else helps. Boy, it's annoying...

Googled it for a long time, looked on Ubuntu forums - nothing.

Anybody can help, please?