Hi - I don't have access to my demo system right now, but I have seen the error you are getting during my development of the demo. I thought that setting IaC mappings as you have done was the resolution.

That said, I think the IaC settings needed to be in place before I created a TF based Cat Item for AWS. Did the cat item you are using exist before you made the IaC settings> If so, as a guess, delete the cat item, rediscover the tf file from the Config management option , recreate the cat item and give it another go. 

It probably wont fix it - but worth a try. Let me know, and I can take a longer look tomorrow.

cheers,

Stu