Comment 1 for bug 578322

Hi tux-seven,
Have you tried the LM 9 Final release?
I am still looking into a more permanent repair for this issue but until it is resolved I would try opening a terminal and trying this command for suspend:

sudo pm-suspend

you could possibly make a custom shortcut to do this task for you temporarily.

As for hibernation try:

sudo pm-hibernate

I found this same issue with Debian linux as well, so it doesn't appear to be a Linux Mint 9 only issue...I will keep looking into this to see if there is a solution to assist your Acer Aspire One (D250) hardware :) I will also elevate this to the debian launchpad to see if anyone there has resolved this issue as well.

Debian source***
http://wiki.debian.org/InstallingDebianOn/Acer/AspireOne-D250-1821