Diagnosis
You tried to expand a line that cannot be expanded.
Generic materials can be expanded to their characteristic levels,depending on the settings for operational Assortment Planning andControl: Sequence of Characteristics

Procedure
If you want to expand to the next planning level, change the settingsfor operational Assortment Planning and Control, either by adding anentry for the desired characteristic level or by enabling the alreadyexisting entry for the corresponding view (overview or detail view).