I should clarify my last message:

Here's what I have placed into the Error() method of my subclassed MSCOMM object, per the MSKB Q291535 article:

LPARAMETERS nError, cMethod, nLine
*~ In THIS.INIT we loop through 10 COM ports, 
*~ attempting to open each with the MSCOMM32.OCX control.
*~ We trap the errors here and if it's an OLE error,
*~ nError will be 1429 (this came from the control).

IF INLIST(nError, 1429, 1426)
*~  Populate an error array and check the OLE message.
	LOCAL aErrArray(1)
	AERROR(aErrArray)
*~ 	If the error msg was "Invalid Port Number"
*~  the control tried to open a port that either
*~  doesn't exist or has nothing on it.
ELSE
*~  We experienced a non - OLE error. Report it.
	mbhError = "Error "+TRANSFORM(nError) + ": "+ SYS(2018)
ENDIF