Detailed Error Information
Module IIS Web Core
Notification BeginRequest
Handler Not yet determined
Error Code 0x800700b7
Config Error Cannot add duplicate collection entry of type 'add' with unique key attribute 'name' set to 'LogoffHandler*'
Config File \\?\E:\Inetpub\VigilantHosting-XD\Install\web.config

ok so in my case i thought it was a permissions problem. Ended up finding a second web.config file in my install dir. Deleted that and the install completed.:)