f16 logout error

[jackson byers]

a recent attempt at logout from f16$ uname -a
Linux f16a9.pacbell.net 3.4.9-2.fc16.i686.PAE #1 SMP Thu Aug 23
18:41:34 UTC 2012 i686 i686 i386 GNU/Linux

via the logout button on "Applications menu"

gave the following error

 logout error
 failed to receive a reply from the seesion manager
Session manager must be in idle state when requesting a shutdown

Multiple attempts same error.

I was forced to:
 # shutdown -r now

I was able to reboot and login again.

Any advice?
Jack