Thanks for your reply Shailendra,
But this

execute this command

begin
ret number;
DBMS_JOB.SUBMIT(ret, 'CALL_WEEKLY;',sysdate,
'NEXT_DAY(TRUNC(SYSDATE),''SUNDAY")+3/24');
commit;
end;

is also not working....can you please help me with any other solution..

Guys, Please through some light on this problem. I'm still struggling with this.

Thanks in advance