SQL & PL/SQL

Dear Gurus...I created the following procedure to implement Event Driven Reporting:

CREATE OR REPLACE procedure ABC.eve_drv_rep as
myPlist system.SRW_PARAMLIST;
myIdent system.SRW.Job_Ident;
BEGIN
myPlist := system.SRW_PARAMLIST(system.SRW_PARAMETER('',''));
system.srw.add_parameter(myPlist,'GATEWAY','http://192.168.1.133/reports/rwservlet);
system.srw.add_parameter(myPlist,'SERVER','rep_appsrv_frhome1');
system.srw.add_parameter(myPlist,'REPORT','y:\02\02\Gry_02_01.rep');
system.srw.add_parameter(myPlist,'USERID','def/xyz@nml');
system.srw.add_parameter(myPlist,'DESTYPE','email');
system.srw.add_parameter(myPlist,'DESFORMAT','PDF');
system.srw.add_parameter(myPlist,'DESNAME','kamrankhan@nishatmills.com');
myIdent := system.srw.run_report(myPlist);
EXCEPTION
when others then
raise_application_error(-20001,'Error sending email.Error: '||sqlerrm);
--Dbms_Put.Put_Line('Error sending email.Error: '||dbms_util.get_detailed_sqlerrm);
END;
/

Procedure is created successfully but when I execute this procedure, I get the following error:

ORA-20001'Error sending email.Error: ORA-20999
ORA-06512: at "Nml.Eve_Drv_Rep", line 17
ORA-06512: at line 1

Can u guess where is the problem?
2ndly I want to know that whether I should give IP address or Application Server Machine Name in GATEWAY parameter?
And in SERVER parameter either I should give the Application Server Machine Name or Report Server name installed on Application Server Machine?
Lastly from where I can get the complete list of Parameters to be added in SRW.Add_Parameter like SERVER, GATEWAY etc.
Please note that we r using Database 10g Rel.2 and Forms and Reports services on Application Services and the report being called was developed in Reports 10g.