For some reason my Linpus system stopped automounting usb hard drives. I could see them as root (sudo thunar) and even give priveleges to other users. So technacly it didnt stop automounting them, it just wouldnt show them to my user. I found the following answer by digging into the aspire one user forums(thx pibri) :
Add a row before “sleep 10”
Add in the empty row: “killall Thunar”
Automount works again….
When he says open he means edit it in your favorite editor. GL