Typically, this message means that there is an error with the JSON. So if you open up the JSON in a JSON editor, it will help you debug the issue immediately.
I suggest using JSON lint to validate the JSON. Let me know if that works! 
FYI: We also have a bug filed that requires fields when creating NoSQL table, even though they are not used. I don’t suspect that is it, but it will be fixed in the forthcoming release.
Thanks,
@AlexBowen