Diagnosis
You attempted to assign the material to an assortment module. It hasalready been assigned to this assortment module for a specified period,however.

System Response
You cannot assign the material to the assortment module twice.

Procedure
Change the selection date on the initial screen. The system will thendisplay the material that you attempted to add to the module and theperiod for which it is listed. You can now change the validity period.