KNX Binding on demo House nearly working

Hello,
I set up a knx test consisting of a switch actor. The good thing: The light can be switched on and off. However, the command is delayed and I get the following failure in the log:


2015-08-23 13:13:05.476 [INFO ] [b.k.i.connection.KNXConnection] - Established connection to KNX bus on 192.168.222.111:3671 in mode TUNNEL.
2015-08-23 13:13:08.480 [WARN ] [.b.knx.internal.bus.KNXBinding] - Value 'OFF' could not be sent to the KNX bus using datapoint 'command DP 0/0/1 Light_Outdoor_Garage, DPT main 0 id 1.001, low priority' - retrying one time: no confirmation reply received
2015-08-23 13:13:11.484 [ERROR] [.b.knx.internal.bus.KNXBinding] - Value 'OFF' could not be sent to the KNX bus using datapoint 'command DP 0/0/1 Light_Outdoor_Garage, DPT main 0 id 1.001, low priority' - giving up after second try: no confirmation reply received
2015-08-23 13:17:20.655 [WARN ] [.b.knx.internal.bus.KNXBinding] - Value 'ON' could not be sent to the KNX bus using datapoint 'command DP 0/0/1 Light_Outdoor_Garage, DPT main 0 id 1.001, low priority' - retrying one time: no confirmation reply received
2015-08-23 13:17:23.661 [ERROR] [.b.knx.internal.bus.KNXBinding] - Value 'ON' could not be sent to the KNX bus using datapoint 'command DP 0/0/1 Light_Outdoor_Garage, DPT main 0 id 1.001, low priority' - giving up after second try: no confirmation reply re

My KNX Binding is:
marco@openhab:/var/log/openhab$ cat /etc/openhab/configurations/items/demo.items | grep knx

Switch Light_Outdoor_Garage         "Garage"         (Outdoor, Lights) { knx="0/0/1+0/0/2" }

Maybe I misunderstood how to read back a value. The ABB actor has connected “output A - switch” to group address 0/0/1 and the “output A - status switch” to group address 0/0/2

Any hints are very welcome.
Marco