It is controlled in the /etc/X11/xorg.conf file.
Look for the section like...
Code:
Section "InputDevice"
Identifier "Synaptics Touchpad"
There are a couple Options that should be able to get rid of the scrolling...
This should turn it off completely...
Code:
Option "UpDownScrolling" "0"
Or set VertScrollDelta to 0...
Code:
Option "VertScrollDelta" "0"
Or set the RightEdge to be way out there...
Code:
Option "RightEdge" "99999"
<EDIT>
I forgot to add... You will need to restart X for any changes to be implemented.