I like the story of reductionist debug, how you distil the problem at each stage, partitioning into what the problem cannot be and what the problem might be. So finally you converged on the ini file, and after the fact it seems so easy to say 'well of course the problem was in the ini file', but was it? As a hardware guy I'm sure you will like the analogy of repairing a cable with break. Best bet is cut it in the middle and one part will surely work. But usually the break is near one end. But which end? Your story proves your logic and method worked, but when you nailed the sucker it was at the wrong end, and you had a whole pile of chopped up bits :)
Andy