Fix issue with AFMMRecordResponseSerializer threading

I created a new pull request with some additional error handling using the built in debugger. @jonbrooks please take a look.
Yep, got it.  That's what I thought, but I wasn't really aware that the object you get from the backgroundContext are different than those from the main context.  (they obviously have different data in some places... but I need to read more about how the different contexts work)

Thanks!