Diagnosis
The InfoObject used in the InfoSource cannot be used for externalmapping. The InfoObject contains properties that make this type of useimpossible.
This is the case for characteristics when
the characteristic contains a conversion routine(for example, ALPHA)
the charactereristic references anothercharacteristic and does not have its own data type defined

Procedure
Change the settings for the for the associated characteristic in theInfoObject maintenance, activate the InfoSource and repeat thegeneration process.