Oracle Forms

I am using Developer Suite 10g (forms 9i, reports 9i) . windows XP.
I am using the following code in WHEN-BUTTON-PRESSED-PRESSED trigger in form to call report.

DECLARE
repid REPORT_OBJECT;
v_rep VARCHAR2(100);
rep_status varchar2(20);
BEGIN
repid := find_report_object('C:\EMP.RDF');
v_rep := RUN_REPORT_OBJECT(repid);
END;

as as result It is displaying FRM - 41219 CANNOT FIND REPORT INVALID ID.
I have used the EMP.JSP also in find_report_object built-in. But there is no difference.
what could be the reason - plz give the solution.

with thanks

by GMS