[Telepathy] telepathy-sofiasip: no sound in ubuntu 12.04

[haeckle]

Hello,

I've just installed the telepathy-sofiasip-package (version 0.7.1-2). 
Everything works fine untill I try to have a call. I can phone somebody 
and he can answer the call but then their is no sound at all. Same thing 
if the other person try to call me. I can answer it, but there's also no 
sound at all.

Here is what the syslog says:
pulseaudio[2225]: [alsa-source] module-echo-cancel.c: Doing resync
pulseaudio[2225]: [alsa-source] module-echo-cancel.c: Playback after 
capture (-24718), drop sink 1600
pulseaudio[2225]: [alsa-source] module-echo-cancel.c: Doing resync
pulseaudio[2225]: [alsa-source] module-echo-cancel.c: Playback after 
capture (-16263), drop sink 1060
pulseaudio[2225]: [alsa-source] module-echo-cancel.c: playback too far 
ahead (15948), drop source 1020
pulseaudio[2225]: [alsa-source] module-echo-cancel.c: Playback after 
capture (-651), drop sink 60
pulseaudio[2225]: [alsa-source] module-echo-cancel.c: push when no link?

Can anybody help me with this problem?

Kind regards,
haeckle

PS: I'm not really sure if that's the right place to ask, but I didn't 
found a more appropriate place for this problem.