Custom message on cocurrent log

Dear all Guru's

How can we handle error in reports..for example..I have a simple report with select query as

     SELECT deptno , deptname from dept where deptno between :P_DEPT1 and :PDEPT2

Now lets say when user run this report ,it fetches no record ..so how can I show in log file that NO DATA FOUND error messages

OR -- lets say any system error comes ..so how can i capture that error and show it with - my own custom message

Regards,

Suryadi