Comment 21 for bug 273323

I'm not sure. I'm fairly sure that there is a problem with acpi-support for Kubuntu users here, but I don't know if it is causing your problem. When you press the sleep button, acpid emits an event which HAL sees, and acpid also runs /etc/acpi/sleep.sh. This script should exit without doing anything if some other process in the users session exists to handle the sleep event. For Gnome users, this is gnome-power-manager (which the script checks for). I'm not familiar with what KDE uses, but the script is looking for kpowersave or klaptopdaemon, both of which I don't think exist. So, in your case, I think /etc/acpi/sleep.sh goes ahead and tries to suspend the machine. In the meantime, something else in your session is using pm-utils to suspend the machine too (powerdevil?).

I could be talking rubbish though - I'm really not familiar with KDE or power management in Kubuntu, but this is how I understand it to work.

It might be good if you could edit your /etc/acpi/sleep.sh and add an 'exit' just below 'DeviceConfig', and then try suspending using the standby button (remember to back the file up so you can restore it afterwards).

Thanks :)