DDS Property Type Changed namespace and now broke.
I think the code and SPs referenced here would still be valid to get the problem sorted:
http://world.episerver.com/forum/developer-forum/Episerver-CMS-6-CTP-2/Thread-Container/2010/5/Object-reference-not-set-to-an-instance-of-an-object-error-Saving-PropertySettings/
Feb 22, 2017 18:02
We have moved an object to a new namespace, and assembly but appears that dds objects property type relies on this heavily. Is there a way to remap the property type?