Problem with video conferencing

Hi,
I have two computers running windows xp on an ADSL Lan.I am able to start a
video conference and/or voice chat between the two computers.On one computer
the video and audio are great and very smooth.However on the other computer
both the video and audio are extremly choppy and words said are
indistinguishable. I have feeling that it may have something to with the
fact that both comuters are within the same LAN. If anybody has a guess
about was the cause for this is or a solution for the problem please reply.

Thanks