acpi doesn't suspend anymore with lidbtn event

[e45rpm]

For some reason, on my laptop, closing the lid doesn't invoke a sleep state. It was working, but it now doesn't work, and I can't figure out why. I can invoke it manually through the "log out" menu option, so the sleep function works, it's just the laptop lid button event doesn't trigger it.

Here is my /etc/acpi/events/lidbtn file, which I changed the last line from lid.sh to sleep.sh

# /etc/acpi/events/lidbtn
# Called when the user closes or opens the lid

event=button[ /]lid
action=/etc/acpi/sleep.sh

I guess my question is, is the 'event' line wrong? I know that the file & path that I am looking for is: /proc/acpi/button/lid/LID0/state where 'state' is the file. If the event line isn't wrong, what else could the problem be?