Visio 2007 Rant
I have been seeing some unexpected application crashes with Visio 2007 and they usually happen when I close the application. I do have Office 2007 SP1 installed but that does not seem to have fixed any of them. The error seems to relate to one the COM add-ins but disabling that does not seem to resolve the problem.
This particular error was a new one for me. After doing a lot of work on a Architecture document - when trying to save the document (for the first time) I see this error - not only is it not very inspiring but also scared the living daylights out of me.
I am quite skeptical now of using Visio 2007 
PS - I was able to recover diagram and did not lose much.