In case anyone else gets annoying messages with their skype running on 64-bit Ubuntu:

1) Doubleclick your volume control
2) Under "Device" select "capture: Monitor source..." and "capture: alsa pcm..."
3) make sure both of these have the volume raised up all the way.
4) open skype, go to options (cntl-o) > Sound Devices
5) For "Sound In", set it to HDA Intel (hw:Intel,0)
6) For "Sound Out", select pulse
7) Try making a test call
8) Post a comment if it worked. I spent wayyy too much time trying to figure this out, hope no one else has to suffer as much :)