SAP Message 1W009 - Data element &1 is already used in key &2 for object type &3

Diagnosis
Data elements must always be uniquely assigned to an object type inorder to be able to generate an object link for a screen field usingits DDIC reference. The data element hier was assigned to more than oneobject type.

Procedure
Make sure that the data element is assigned to only one object type orto a supertype.