Lets look at this problem from another perspective.
You might have a jack without a phone that has damage either by corrosion or phisical damage. This jack might be still connected to Partner. Is there same amount of cables plugged in into ACS as the amount of phones?
Also are you an Avaya BP? if you buying Avaya business phone system from anybody other then Jenne or Catalist you can very easy have bad processors in your hands.
