Devices/Channels are triggered automatically

[Johannes01]

I use DVC3 128 to control some lights in my home.
I use some simple dimmers and some RGB-LED.
All the configuration of scenes and control with the software workes well.
I use also the external triggers on HE10 ports to Switch some predefined Scenes.
This also works well.

The only problem I have (and ist is a big problem which makes the DVC3 unusable for me):
some cannels or Scenes are activated randomly and automatically without triggering them with the switches on the external trigger-ports.
This happens somtimes within minutes, sometines also within hours.
So when I leave my home, I cannot be sure, that the lights stay off until I come back, because they switch automatically ON in this meantime without any manual action.

Can anybody help me?