New to SCCM, only just started with CM2012 RC (Build 7700)
I too have the same issue with the Software Center/Application Catalog.
I enabled WCF Activation as per an earlier post, plus rebooted the server, update the agents, etc and now the webpage just repeately scrolls between website found and redirecting, then eventually fails with an IIS error.
I have tried removing both Application Catalog site roles and running the cmd line for .net 4 - this does nothing.
Any help would be great appreciated.