Cursor FOR LOOP goes into Exception

Dear All

I have written a plsql program to create jobs in HRMS. When I execute this program LOOP is not executing it is directly goes into Exception. On printing SQLCODE and SQLERRM out is "-20001 ORA-20001: :". My cursor query is

SELECT TT.JOB_CODE,TT.JOB_DESCRIPTION,TT.STATUS,TT.ERROR

            FROM XXAASL_HR_JOB TT

            WHERE TT.STATUS IN ('N','R')

            ORDER BY TT.JOB_CODE

            FOR UPDATE OF TT.STATUS,TT.ERROR;

Kindly suggest what mistake i am doing.