Duplicate Excise invoice number for same supplier

[dhiman081]

Hi,
While receiving if user punch a duplicate excise invoice number for a particular Supplier. System Accept it but the receipt error out with following error:-
RVTTH-190: ORA-20501: Duplicate Excise invoice number for same supplier site
ORA-

Cause: A SQL error has occurred in RVTTH. The SQL error is &LSQL_ERR.

Action: Take note of both this error number and the actions you were t

IS THERE ANY WAY WHENEVER USER PUNCH A DUPLICATE EXCISE INVOICE NUMBER SYSTEM SHOULD SHOW A POP UP / MESSAGE???? ---- Excise Invoice Number Already Exists
Please help me if some know how to overcome this error??

Regards