Error creating trigger

[Gil Katz]

Hi guy's
Whats wrong with this one?

Create trigger app after update on app_machines
for each row
begin
if NEW.OCCUPIER != NULL Then
insert into history (MACHINE_NAME,USER_NAME,FROM_DATE,TO_DATE)
values (NEW.MACHINE_NAME,NEW.OCCUPIER,NEW.FROM_DATE,NEW.TO_DATE);
End If;
End;
Thanks
Gil