If I had to guess, I would say that something has barfed. That descriptor does not do you much good, but you did ask what this is
as opposed to how to fix it :-)
I would uninstall everything related to Nvidia video, reboot and run with the OS video drivers
for a while just to see if it happens using the generic OS drivers. Then try the latest drivers from Nvidia. If the problem returns. Uninstall the Nvidia video stuff again and hunt for an older version.
Also, when installing stuff from Nvidia, install the minimum number of things while you chase this annoyance down.