Comment 53 for bug 428115

Daniel, the bug title is "does not lock screen on lid close" (which is what g-p-m does). Also comment 51 will actually _break_ it:

  gconftool -s --type string /apps/gnome-power-manager/buttons/lid_battery blank

This configured g-p-m to _not_ suspend any more on any lid actions. I suggest to revert with

  gconftool --recursive-unset /apps/gnome-power-manager/buttons/

to restore the defaults again.