I recently had to fiddle with my Ubuntu Linux 11.04 machine to get it working after breaking my FakeRAID mirror. Unfortunately when I tried to launch Disk Utility, it showed a blank canvas - no drives were listed. Long story short, my specific problem turned out to be permission related. Once I changed the file below like this:

-rwsr-xr-- 1 root messagebus 47528 2011-03-20 15:36 /lib/dbus-1.0/dbus-daemon-launch-helper

all was good again.