There is one issue when user try to go to lines level one error is coming out :
APP-FND-01564: ORACLE error 1422 in FDFGVD
Cause: FDFGVD failed due to ORA-01422: exact fetch returns more than requested number of rows.
and when he click on the DFF field the error is :
APP-FND-00730: This flexfield has an invalid value set. It may use a special value set that uses an Edit event user exit, and the user exit has failed. If you are using a form on a graphical user interface (GUI) you may have an invalid value set of a different type, possibly a table-validated value set where the table or view does not exist or where there is an invalid WHERE clause.
Please let me know its a technical issue or functional issue and how to resolve it.I have used all the options but unable to resolve it.
Please check the SQL Statement that is executed during the error. Seems to be more of a technical issue, but you can ascertain that only after checking the SQL query's behavior in your instance.