Exchange 2007 Server EMC is throwing error "An IIS directory entry couldn’t be created.The error message is Access is denied. HResult = -2147024891"

Exchange 2010 installation into existing Exchange 2007 SP2 Organisation. Getting the below error when attempting to view the Client Access roles Outlook Web App & Exchange Activesync in the Exchange 2010 EMC.  You get following error  EMC 2010 – Client Access Server Configuration : An IIS directory entry couldn’t be created. The error message is Access is denied. HResult = -2147024891
 
 
 
 
 
Turns out, if we have Exchange 2007 server in co-existence with Exchange 2010 the security group “Exchange Trusted Subsystem” needs to be a member of Local Administrators group on an Exchange Server 2007 box