System76 Pangolin -- Lucid Lynx -- Cursor Jumps when driven from Touchpad

I have a System76 Pangolin. I think I'm running Lubuntu 11.04, but I'm sure the problem also manifested with plain Ubuntu 10.04 LTS Lucid Lynx.

When I slide my finger across the touchpad, then at a certain invisible vertical line near the right, the cursor jumps a long way to the left or right, the same direction I'm moving my finger. The line is some 1cm maybe 1.5cm to the left of the scrollbar indication. A "long way" is about 3/4 the width of the screen. Any help for this?