What this error indicates is that the attribute has been deleted from The Education Edge (EE), and it was still being used on the form in NetCommunity. The form is still trying to map information to that attribute.

Attribute fields use an ID number to process the information. Adding the attribute back to EE won't resolve the problem because each attribute is tied to a specific ID, and when you add a new attribute it generates a different ID. 

The form will need to be manually entered into The Education Edge.

To correct the error going forward, correct the form on the NetCommunity website to remove the deleted attribute.