Crystal Reports literal does not match format string

Message


     using crystal XI with oracle database and creating a command. I keep getting an error on this portion of the sql query
 
where 
to_date(schema.table_name.start_date,'DD-MON-YYYY') >='01-JAN-2009' 
 
have also tried 
 
to_date(schema.table_name.start_date,'DD-MON-YYYY') >= 
to_date('01-JAN-2009','DD-MON-YYYY')
 
have also tried 
 
dd-mm-yyy
 
the error is ORA-01861 String literal does not match