No system sounds in Gnome

My not even a week old Opensuse 11.1 installation with Gnome Desktop doesn’t play any system sounds except for the start up sound. Every other sound (games, banshee) is working fine.
When I go to audio preferences all the test sounds are working and I can even hear the examples in the system sounds tab. When I activate the button sounds (those that play when you click on the computer icon or maximize a window) they work either.
Only the sounds for system shut down, alarm, empty the trash etc. aren’t working although they seem to be activated.

I found several forums in which this problem was discussed however they all where about other distributions (Ubuntu, Debian, Gentoo) and I’m not able to use anything mentioned in these forums on Opensuse. They all had the Gnome desktop in common.
One example: #121 (GNOME system sounds don’t work) – PulseAudio](

I had the problem myself when I was using Ubuntu until a week ago.

I would be very glad if somebody could help me fix this.