Diagnosis
You want to create a batch for a material with material type &V1& and have not entered a batch number. In Customizing, you havedefined for this material type that batch numbers cannot be assignedexternally.

Procedure
You can either change the Customizing setting for material type
&V1& to allow batch numbers to be assigned externally, or you donot enter a batch number and instead let the system assign the batchnumber automatically.