Hello - I have gone through process of testing mic and sound - all work on my new Lenovo but whenever I try to make or receive call via Skype, it says "Problem with playback device". On the other end, it tells the caller I need to update to new version of Skype. I recently did this - I am running Skype 5.5.
I'm not sure what operating system you are using, but I have an Windows XP version of the fix. If you are running Vista or Windows 7 the procedure should basically be the same. Here is the link for the instructions:
Skype Enterprise Support