Message: The set local node address is already in use

[mulderm 3]

Hello, I have a mpi-network with adres:0 = modem, adres:2 = S7-300 plc, adres:3 = Touch-panel When I start up a step 7 program and I will monitoring a block everything works perfect. And then start-up wincc with have an integrated project and starting the Run-time I get no connection with the panel (seeing ####). Then when I will going monitoring the same block in the Step 7 program I get the message: "The set local node address is already in use" Looking in the set pc/pg interface: adress is 3 (was 20). Changing the adress again in 20 and doing as above descriped the same problem appear. Opening the set pc/pg interface again: the adress-value is again changed from 20 to 3. Who can explain this and what is the solution? Greetings, mulderm