Issues while hosting Restful WCF services in IIS

When i hosted my Hello World WCF Restful services, i faced below issue

The requested content appears to be script and will not be served by the static file handler.

My application is using 'DefaultAppPool', For reasons unknown to me, running the below did work. 

c:\Windows\Microsoft.NET\Framework\v4.0.30319\aspnet_regiis.exe -i

But soon after this i ran into below issue

"Could not load type 'System.ServiceModel.Activation.HttpModule'"

For reasons unknown to me, running the below did work :(.   

c:\Windows\Microsoft.NET\Framework\v4.0.30319\aspnet_regiis.exe /iru

http://forums.asp.net/t/1432329.aspx/1 

http://www.fredmastro.com/post/HTTP-Error-40417-Not-Found-e28093-Using-WCF-SVC-Service.aspx 

http://support.microsoft.com/kb/2015129