Diagnosis
Only those characteristic values can be assigned to anothercharacteristic as delta nodes that are not used anywhere else inhierarchies. But &v1& is used since period &v3& in hierarchies ofversion &v4& below node &v2&.

System Response
V1 cannot be used at present as a delta node.

Procedure
Assign another delta node.
Or delete all usages of this characterisitc value in hierarchies.Subsequently this value can be used as a delta node.