Diagnosis
You have used the field name of a subfeature in the decision operation.Its main feature has, however, not yet been assigned to this operation.

Procedure
An error has occurred because you have not assigned the operation tothe main feature. The field name used in the decision operation is thusnot valid for the main feature and an error occurs.
- Place the feature operation somewhere in front of the decisionoperation.
or
- Mark the field name as valid for the main feature structure.