Fatal error at 83% shouldn't be related to our sceneries but, most likely, something in a terrain scenery addon. The largest part of our scenery is not loaded by FSX in the "Loading scenery" phase but, instead, is loaded only *after* the airplane is already on the airport ready to fly.
In fact, there's usually a slight pause of a couple of seconds when the loading is finished, when you don't see any of our objects apart from the jetways, and then our loading starts.
That's why I don't think a crash at 83% is depending on any of our sceneries, since almost nothing is loaded at that stage (but of course, most of the rest of installed sceneries are loaded exactly then).
In any case, it would be helpful undestanding what .dll (FSX module) has crashed, this might give an hint of what the problem is. If you can't get error details when FSX crashes, it should be possible to find the error in the Windows Event Viewer, which is in the Control Panel, under the System Administration tools.