I am working with QA team on this issue and I will update you all soon.
I cannot believe this is happening again. After installing SP2 my .NET code won't compile because it can't find AecXBase and AecXUIBase. I'm totally gobsmacked that Autodesk have done it again.
Resolution given in the following Blog post should fix the issue related to SP2 also.
Please let me know if anyone needs help here.