Dear Jeremy!
I looked through your link and its still not obvious to me what's wrong.
I really tried using different namespaces (Autodesk.Revit.DB.Macros and Autodesk.Revit.UI.Macros).
Is it possible that something changed since 2014 API? I'm using Revit 2016 and Visual Studio 2013 (.Net 4.5 framework). May be some kind of attribute could be the reason..
Would you be so kind to try it yourself? If you are succesfull at it then it's got to be mine PC problem
By the way, have you seen this topic http://forums.autodesk.com/t5/revit-api-forum/automatic-space-creation-problem/td-p/6553375 ?
Thanks in advance!