Could not load type ‘System.ServiceModel.Activation.HttpModule’ from assembly ‘System.ServiceModel, Version=3.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089’.

This is caused when 4.0 components are not properly installed on the IIS Server. To resolve it, you can run this command:
>aspnet_regiis.exe –iru

That exe is found here:

• 32-bit systems: %SystemRoot%\Microsoft.NET\Framework\v4.0.30319
• 64-bit systems: %SystemRoot%\Microsoft.NET\Framework64\v4.0.30319