i just typed in the error message text into google search engine, and i found huge amount of links, but there are very much different topics. for instance
http://www.softricks.com/wwwboard/messages/110.html
someone mentions this message with a calendar
http://www.mghansen.de/errormsg.html
here is that message in german and in the beginning of the page
the author makes notice of the calendar problem again.
sounds familiar(i dont know where to find calendar myself)
so it seems to me that its a known problem.
maybe try microsoft's helpdesk.
are you experiencieng these messages with a certain number of pages or is it 'random'?
hope this can help you out somewhat. if i can find some time
(quite busy with school right now) ill try to look into it too in the weekend