Indigo does not communicate to Appliance module

New to Indigo and seeming to get nowhere! Have RFX433 apparently working, so added X10 Lamp Module, set to House code H and id 1 (which is correct and works from the mini-timer). Pressing Turn on or Turn off does nothig. Setting up schedules to turnAllOn (or OFf) also does nothing. Event log says:
RFXCOM Error initialization failed (retrying in 10 seconds)
RFXCOM Error Error in plugin execution runConcurrentThread:

Traceback (most recent call last):
File "plugin.py", line 290, in runConcurrentThread
File "/Library/Application Support/Perceptive Automation/Indigo 6/Plugins/RFXCOM.indigoPlugin/Contents/Server Plugin/RFXTRX.py", line 1842, in startComm
<type 'exceptions.AttributeError'>: 'NoneType' object has no attribute 'close'

RFXCOM Error plugin runConcurrentThread function returned or failed (will attempt again in 10 seconds)

Any clue as to what I'm doing wrong?

[MODERATOR NOTE]: Moved to RFXCOM plugin forum.