Diagnosis
You want to delete a material which is entered as the pricing referencematerial for other materials in the material master. An error occurreddeleting one of these materials.
The pricing reference material and all materials to which this pricingreference material is assigned can only be included in a promotion as agroup, and therefore only be deleted as a group as well.

Procedure
Correct the error for the material(s) which the system could not deleteand then execute the function again.