My sound always worked, including after the pulseaudio transition in Hardy. gstreamer-properties sets the default out- and input to pulseaudio, and has done so, sucessfully, for quite a while. After running a full-upgrade on Monday (I had performed none since Friday morning), I noticed that totem-gstreamer had no sound.
Other video players that support pulseaudio (xine, mplayer) have no sound when using pulseaudio either. When I run the test in gstreamer-properties, I see the error message from the subject. When setting gstreamer to Alsa, the test succeeds; xine and mplayer sound is also fine when using alsa.
There are errors in the logs, grep pulse /var/log/* gives:
/var/log/syslog.0:Mar 25 21:26:57 chronic pulseaudio[16432]: alsa-util.c: Error opening PCM device hw:0: Device or resource busy
/var/log/syslog.0:Mar 25 21:26:57 chronic pulseaudio[16432]: module.c: Failed to load module "module-alsa-sink" (argument: "device_id=0 sink_name=alsa_output.pci_8086_27d8_sound_card_0_alsa_playback_0"): initialization failed.
/var/log/user.log:Mar 25 21:26:57 chronic pulseaudio[16432]: alsa-util.c: Error opening PCM device hw:0: Device or resource busy
/var/log/user.log:Mar 25 21:26:57 chronic pulseaudio[16432]: module.c: Failed to load module "module-alsa-sink" (argument: "device_id=0 sink_name=alsa_output.pci_8086_27d8_sound_card_0_alsa_playback_0"): initialization failed.
/var/log/user.log.0:Mar 19 00:02:07 chronic pulseaudio[6789]: shm.c: shm_open() failed: No such file or directory
/var/log/user.log.0:Mar 19 00:02:07 chronic pulseaudio[6789]: pstream.c: Failed to import memory block.
/var/log/user.log.0:Mar 19 18:34:46 chronic pulseaudio[8145]: shm.c: shm_open() failed: No such file or directory
/var/log/user.log.0:Mar 19 18:34:46 chronic pulseaudio[8145]: pstream.c: Failed to import memory block.
lspci:
00:1b.0 Audio device: Intel Corporation 82801G (ICH7 Family) High Definition Audio Controller (rev 01)
It sounds like something else is using alsa, and PulseAudio can't access the sound device, as pulseaudio talks to the hardware directly, instead of using dmix.
Check that you have no other sound related apps running, excluding the mixer applet. One way to do this is to check whether any device nodes are open in /dev/snd.