Diagnosis
You want to use a change number that has aneffectivity type (such asserial number range) to define its effectivity, not a valid-fromdate.

System Response
The system determines the effectivity data from the change masterrecord and makes any further checks that are relevant to the object.

Procedure
Check whether the settings for parameter effectivity are defined forthe object you want to change.
Example
You want to allocate a material to a class of class type 001, and entera change number that has an effectivity type to define its effectivity.The ECM (parameter) indicator must be set. You setthis indicator in Customizing for the Classification system underMaintain object types and class types.