What causes the msg "input queue lock broken" on the console?

[Len Schwer]

I have a Sun SLC running OpenWindows 2.0 under SunOS 4.1.1. I leave my
machine on all the time with the screen saver (I've tried both the
Openwindows and SunView) running. 

About three times in the past 5 months I have started to use my machine,
two returns to get past the screensaver and password prompt. Since I am
still logged in, my windows appear and then the first key I type is
replicated in the current window and hogs the entire CPU. I see the msg
"input queue lock broken" in the console window, but that's the only clue.
I have to power down and reboot to regain control of the system.

Any ideas?  Thanks,  --Len Schwer   schwer at unix.sri.com