Diagnosis
You have tried to change the assembly type for a requirements class tovalue '&V1&'. The value in the database is however 'V&2'. The change isnot permitted and has therefore led to this error message.
You can do any of the following:
Change assembly type from ' ' to another value.
Change assembly type from '1' to '3'.

Procedure
Use another requirements class for the Customizing you require. Ifnecessary, set up a new requirements class.