Error response when fields could not be found

Updated for all types.

`$@` is a special variable which contains an error message.  You'll only get this if you've performed an `eval`, so in this case I expect it to be empty in all cases.  (It's the same for every case where you've used `$@` outside of the context of an `eval`).  You may just want to check the master branch and see what the error message was when the eval was being used to see if we're losing any useful information.