I've been through all the other similar posts I can find on this, and they suggest creating/editing files that seem to make no difference, sorry. I have a new computer (Acer Aspire V3 771G) running Ubuntu 13.04, but touchpad scrolling won't work. I've tried enabling everything touchpad related in the dconf editor, and even installed the unity tweak tool and bodged settings around in there, but nothing seems to work. Can anyone offer me any advice as to what I should try next? Thanks, Doug.
I found the answer at http://nwoki.wordpress.com/2012/10/02/multitouch-fix-for-alps-touchpad/ for my Acer Aspire V3 771G.
The version I've downloaded was 1.3, so replace every instance of psmouse-alps-dst-0.x with psmouse-alps.1.3 (so, without the dst). Also, I did not change the alps.c file as mentioned on the website.
After ending every step I can (finally) use my touchpad. I only have to get used to spreading my fingers a little wider than I am used to with a synaptics touchpad.