This may seem as a duplication of:
Synaptics Touchpad - cursor moves around when just 'tapped' after Ubuntu 12.04 upgrade
I tried that solution and it works! Setting the FingerHigh and FingerLow values really does the trick, but the xorg.conf file gets renamed to xorg.conf.xxxx (xxxx being random numbers) and then the values of FingerHigh and FingerLow are not the ones I chose anymore.
Any suggestion on how to make this xorg.conf file persistent?
Thanks!