I cannot hear the other side at all.
The sound system on the mac is fine - I can hear author audio, including beeps and ringtone from skype. I already tried reinstalling skype but that did not help.
Can you help?
Maybe the issue is at the other side, not at yours...
Did your contact check his/her audio settings by calling 'echo123' (Skype Test Call) to be sure that they are configured correctly ?