Don't scare him. 80% it's the Php dll. 12% another IIS extension. 7% The web server.
Why would a driver randomly corrupt the IIS memory space *just when the user accesses mediaiki*? Wait, it can be a DRM driver installed by sharepoint!! Censorship! I get viagra ads on the butterflies article after installing a wikipedia toolbar from w1kipedia.ru!!! Wikipedia administrators are evil!
Quickly! Revert to the Wrong version! http://meta.wikimedia.org/wiki/The_Wrong_Version