Irresponsive Touchpad

[DaveGK]

I'm experiencing a rather strange touchpad behaviour - sometimes it's 
fine, sometimes I have to tap it a few times to get result. Also, for 
some reason there's no touchpad tab in mouse preferences window. I did 
check in gconf-editor and touchpad is checked. An attempt to install 
GSynaptics wasn't successful: all seems fine, but when I try to start 
it, I get:
" GSynaptics couldn't initialize. You have to set 'SHMConfig' 'true' in 
xorg.conf or XF86Config to use GSynaptics "
Now, there is no SHMConfig in the xorg.conf and I don't know what to add 
(i.e. there must be a subsection etc).

System: Ubuntu Jaunty 64-bit, ext4. Acer Aspire 7735G

Appreciate any help, but please be gentle - a newbie here :))

-- 
Cheers,
Dave