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