I\'m running Windows 7 Ultimate (64 bit) using Visual Studio 2010 RC. I recently decided to have VS run/debug my apps on IIS rather than the dev server that comes with it. <
This worked for me and it might be useful to another one.
Maybe all components required are not present or/and not all are registered correctly. In order to solve this, try to uncheck all options inside Control Panel -> Turn Windows features on or off -> Internet Information Services -> World Wide Web Services -> Application Development Features, uncheck all options and recheck all then reset the IIS and check if the problem is solved.