Are you using the 'evdev' driver for mouse, if you don't know then you probably are, in which case add or modify your '/etc/X11/xorg.conf' as follows:
Code:
Section "Module"
SubSection "extmod"
Option "omit xfree86-dga" # don't initialise the DGA extension
EndSubSection
EndSection
So in the Module section add that part.
I'm pretty sure this will solve it, because this mouse going to bottom of the screen is exactly what happens in all SDL games if you don't add the above to xorg.conf.