Suspend menu option won't suspend MacBook in latest Gutsy

Binary package hint: gnome-power-manager

In the latest Gutsy Gibbon (currently Tribe 2 with some updates), I am unable to suspend my MacBook (Core Duo) using gnome-power-manager. Both using the menu in the GNOME system tray and setting g-p-m to suspend on lid close has no effect. On occasion (about every other time I attempt to suspend, I receive an "Action Forbidden: Policy Change is not valid. Please wait a few seconds and try again" error message from g-p-m.

 In Tribe 1 and for a few weeks after that, I was able to suspend the machine using those methods without problems. Furthermore, I am able to suspend my MacBook by using the pmi command (sudo pmi action sleep in this case), hence the issue seems like one with g-p-m and not a kernel issue.

Here is the lines from /var/log/acpid when I attempt to suspend by closing my laptop's lid:

[Thu Jun 28 22:37:04 2007] received event "button/lid LID0 00000080 00000004"
[Thu Jun 28 22:37:04 2007] notifying client 5059[108:114]
[Thu Jun 28 22:37:04 2007] notifying client 5226[0:0]
[Thu Jun 28 22:37:04 2007] executing action "/etc/acpi/lid.sh"
[Thu Jun 28 22:37:04 2007] BEGIN HANDLER MESSAGES
[Thu Jun 28 22:37:04 2007] END HANDLER MESSAGES
[Thu Jun 28 22:37:04 2007] action exited with status 0
[Thu Jun 28 22:37:04 2007] executing action "/etc/acpi/actions/lm_lid.sh button/lid LID0 00000080 00000004"
[Thu Jun 28 22:37:04 2007] BEGIN HANDLER MESSAGES
Laptop mode disabled, not active.
[Thu Jun 28 22:37:05 2007] END HANDLER MESSAGES
[Thu Jun 28 22:37:05 2007] action exited with status 0
[Thu Jun 28 22:37:05 2007] completed event "button/lid LID0 00000080 00000004"