SAP Message WX047 - Acct group for plant profile & uses internal no.assignment, not possible

Diagnosis
The plant profile refers to an account group for which internal numberassignment has been defined.
Only external number assignment is possible when you create a plant.

Procedure
If you are authorized, you can assign the account group in question anumber range with external number assignment.
IF &DEVICE&='SCREEN'
Proceed
ENDIF