Diagnosis
You want to define number assignment for the object type.

System Response
Defining the number assignment is not allowed. Possible reasons arelisted below:
You are trying to define number assignment for this object type on thetop-level object (such as locality) of the hierarchy. When the objecttype of an object is designated as a top level of the hierarchy, thenthe system automatically numbers the objects across all clients. It isnot necessary to enter number assignment specifically.
You are trying to define number assignment for an object type that isnot allowed in the architectural object type hierarchy.

Procedure
Remove number assignment for this object type in the current object.