which field are you putting this in (Audio Conferencing)? if so you should configure two separate pipelines:
Sound playback: audioconvert ! audioresample ! gconfaudiosink profile=chat
Sound capture : gconfaudiosrc  profile=chat ! audioresample ! audioconvert

If that does not help, could you run this from a terminal and attach the log here:

GST_DEBUG="*:4" gnome-sound-properties 2>debug.log

Created attachment 95501 [details]
log from gnome-sound-properties (compressed)

We are seeing a similar bug on Mandriva system (bug http://qa.mandriva.com/show_bug.cgi?id=28679) :

it is only when using microphone included in webcam, which don't provide an real mixer (according to hadess).

Using the same pipeline with gst-launch-0.10 works fine BTW

here is one part from the log that looks suspicious:

0:00:06.564781000 16427 0x805d068 WARN                  alsa conf.c:3949:snd_config_expand: alsalib error: Unknown parameters 1
0:00:06.564882000 16427 0x805d068 WARN                  alsa control.c:909:snd_ctl_open_noupdate: alsalib error: Invalid CTL default:1
0:00:06.565016000 16427 0x805d068 WARN                  alsa gstalsamixer.c:69:gst_alsa_mixer_open: Cannot open mixer for sound device 'default:1': Argument invalide

but it goes to playing. later downwards I don't like this (goes from around 7 sec to the end):

GST_SCHEDULING gstpad.c:3975:gst_pad_pull_range:<src:proxypad6> pullrange returned buffer of different caps

Thanks for taking the time to report this bug.
This particular bug has already been reported into our bug tracking system, but we are happy to tell you that the problem has already been fixed. It should be solved in the next software version. You may want to check for a software upgrade.


*** This bug has been marked as a duplicate of 471364 ***