cannot logoff/shutdown properly

["Manu Hack" <manuhack@gmail.com>]

Hi all,

I'm running lenny.  recently after upgrade to 2.6.21, I found that I
couldn't logoff/shutdown properly from KDE/GNOME/windowmaker.  By
properly I mean whenever I choose logoff, usually KDM/GDM can take
over and give me a login prompt but now it just goes blank and nothing
can be done (including alt control back or F1) but pressing the power
button to turn it off.

What could go wrong?  Thank a lot.

Let me know what further information you need to investigate the issue.