AppFabric Installation Limitation
AppFabric is picking up the pace in the market, AppFabric make your development easier by managing the web and composite applications which runs on IIS
Appfabric provides deployment and management of WCF services and also you to capture only specific data . AppFabric provides you with the powershell cmdlets for creating custom management scripts.
Architecture includes Dublin , Velocity which integrates with Application Server role
One major constraint of AppFabric is that you cannot install it windows 2008 R2 Web Server Edition which is not documented J by Microsoft. So if you are trying to install AppFabric the installation stops near deployment phase.
So one who is thinking to install AppFabric on Webedition should need to wait for the workaround.
Windows Architecture 