Comment 20 for bug 9185

Sounds like this was fixed by:

linux-source-2.6.9 (2.6.9-2) hoary; urgency=low

  Changes by Fabio M. Di Nitto:
[...]
  * Update disable-lapic-in-acpi-power-off.dpatch with a portable fix from
    http://bugzilla.kernel.org/show_bug.cgi?id=3643.
    Add patch disable-lapic-in-acpi-power-off-2.dpatch.

Please reopen if someone is still experiencing this issue on the same hardware.