[Mediawiki-l] Error when editing after upgrade

[Roy Anger]

I imagine the following has been covered before, but I'm having trouble 
locating specific information. I have just upgraded my wiki site from 
1.5.6 to 1.6.8. Now whenever I edit a page I get the following error:

*Sorry! We could not process your edit due to a loss of session data. 
Please try again. If it still doesn't work, try logging out and logging 
back in.

*If the solution has been covered before, please point me to it. I would 
greatly appreciate that.


Thanks,
Roy