Unable to manage IIS 6.0 by using Server Manager if two threads access IIS 6.0 at the same time

I ran into this funny problem in the production environment recently. When launching IIS Manager (inetmgr) in the WFE servers, it shows the server, but it does not allow expanding of the tree to reveal the standard Web Sites, Web Application Pools sub trees.

A hot fix has to be applied to fix this problem. More info at MS KB946517.