Comment 2 for bug 51591

Same during a dist-upgrade to Edgy. acpid held up ubuntu-desktop saying acpid: can't open /proc/acpi/event.

Running /etc/init.d/acpid stop and then /etc/init.d/acpid start returned the same message. Don't know if this is regular or not, but sudoer and root can't delete /proc/acpi/event, even after it is 'stopped'. A cat of /proc/acpi/event shows that it doesn't change.

Was able to bypass the error by killing the acpi process.