SAP Message WB016 - Version no. & for customer & and assort. list type & already exists

Diagnosis
You attempted to create a new assortment list version in versionmanagement. The version number was already assigned, however.

System Response
The version cannot be created.

Procedure
This error can occur if the lead time or the cycle length for theassortment list type is reduced in Customizing. If this is the case,you should delete the old versions so that the sequence of the versionnumbers coincides with the validity periods again.