When I click on sleep [wherever it is, guidance power manager, plasmoid, or shutdown menu) it actually does nothing. I've checked "when laptop lid is close do" option to ---> "suspend to RAM", but all it does after closing the lid is lock the screen. Although pm-suspend called by root in console works perfectly. I don't have any idea what is wrong, and where to look about any errors.

Try looking in the file ~/.xsession-errors immediately after clicking "Suspend".

I'm also affected by this problem.
I use KDE 4 on Slackware 13.0, and I just tried to check this ~/.xsessions-errors after trying to suspend. There is no such file after nor before trying to suspend.

It appears that your distribution does not automatically use that file for some reason. How did you start KDE? Using a login manager ( graphical ) or with "startkde"?

bcooksley wrote:It appears that your distribution does not automatically use that file for some reason.

I had it. I can't recall exactly but there was something like "can't link with ck-connector". Feature started to work after installing ConsoleKit and recompiling KDE.

ensure that your user is a member of
83(plugdev),84(power),86(netdev)
groups. otherwise the dbus session doesn't have rights to the power management.