No Return??

I'm getting a little frustrated with this problem.

Can anyone tell me what is wrong with the following code.

I have tested the portions separately and they all work.

When I try it as a whole I get the message "control reached end of trigger
procedure without RETURN."

Any help greatly appreciated.

Bob

Declare
pumpnumber integer;

Begin

Select count(*) Into pumpnumber From p_id.devices, p_id.processes
Where device_number = '11'
and p_id.devices.fluid_id = p_id.processes.fluid_id
and p_id.processes.ip_op_equipment = 'op';

If pumpnumber = 1 then
Update p_id.devices
Set number = '#1'
From p_id.processes
Where p_id.devices.number is null
and p_id.devices.device_number = '11'
and p_id.devices.fluid_id = p_id.processes.fluid_id
and p_id.processes.ip_op_equipment = 'op' ;

Else If pumpnumber = 2 Then
Update p_id.devices
Set number = '#2'
From p_id.processes
Where p_id.devices.number is null
and p_id.devices.device_number = '11'
and p_id.devices.fluid_id = p_id.processes.fluid_id
and p_id.processes.ip_op_equipment = 'op' ;

End If;
RETURN NULL;
End If;
END;

I have tried 'Return New' and 'Return Result' without luck, and if I leave
off either of the two 'End If ' statements the procedure returns an error.

B