I've got a problem with suspend to disk in ubuntu 12.04 (it worked perfectly in 11.10).
I've installed the pm-utils package, but whenever I issue:

sudo pm-hibernate

it appears the screen that notifies me that the s2disk image is being created (and it is), the system powers down, and then it powers up again, taking me back to where I was...

What can I do to prevent the system from rebooting?

I've tried to modify many options in the bios (S1, S3, no reboot after failure etc)

thanks