I have a 2003 7li built in February.
When I bought the car at the beginning of this year, the factory fit ACC never worked on it, to be fair the garage never advertised the fact the car had ACC or the comfort access (which only works on one door) and the price was reflected by this.
The error you are seeing from the MMI are the same that I get, pre and post facelift MMI. I am just getting my feet wet with INPA, but only last night got the error codes from the ACC module. The bit I was pleased about ( not only that the acc responds) was the fact that the error messages had mileage recorded when they occurred which is well within the mileage that I have owned it. I suspect the error are each time I try to activate it and it fails, at least I know the module is responding.
I have never been able to read the module in ncsexpert.
Have you got the option set in the VO $541 I think, and remove $540
I will be working my way through other module error codes to see if they give a clue.
In INPA there are some options for ACC but I haven't translated it yet to find out what it's telling me, have you used that section and does it allow you to configure the module?