Hi Murali,
I am not much familiar with it. But I just found one information on this error as:
CAUSE
WBS element v1% could not be assigned unambiguously to a grouping element. v1 has been assigned to several grouping elements tha have the same validity (plant/MRP group).
SYSTEM_RESPONSE
Processing is not continued
WHAT_TO_DO
Check your entries for WBS element v1 in the assignment table and make sure that all the grouping elements, that v1 has been asigned to, differ in the assignment to a plant/MRP group in the validity table
Now, what I understood from it is that you need to check in assignment table whether WBS 2700150 has been assigned to a different MRP group to what you are assigning now. You will have to remove that earlier assignment if permitted and proper than you can make a new assignment.
Let me know if my assumption is right..
Thanks