Comment 23 for bug 354220

I did not test with the latest alpha, because that would require upgrading my personal productivity system to a non release version. That being said, I no longer see these error messages. They likely were fixed by some update. Here are my new versions:

virtualbox-3.1 3.1.4-57640_Ubuntu_karmic (upgraded since pb)
pulseaudio 1:0.9.19-0ubuntu4.1 (not upgraded since pb)
linux-image-2.6.31-19-generic 2.6.31-19.56 (upgraded since pb)

Pb automagically disappeared. Either fixed in kernel/vbox or worked-around by vbox team. You can close the defect as far as I am concerned.