Customer Portal 2011 - An error has occurred while loading content required for this feature

It's just a quick post here, hopefully to save your time: if you deploy the Customer Portal for Microsoft Dynamics CRM 2011 on a Windows Server 2008 machine or VM, and get this error message when editing the page: "An error has occurred while loading content required for this feature"

Windows Event log doesn't say anything about it, but if you fiddler it, you will find a 404 error related on a Cms.svc endpoint:

Solution:

To solve this issue, firstly make sure you have installed the WCF activation features.

Also you have installed Windows Server 2008 R2 + SP1 , you need to install the Microsoft .NET Framework 4 KB2468871

Thanks MVP Shan McArthur from Adxstudio to point out on his blog: