I did not edit it - it happened on its own, maybe while I installed it.
You must have edited it a long ago. It's not a file that comes with GSX only, we used it since years. It's not possible it would get corrupted with just installing a product, since all our installers use only standard Windows API function to add/remove keys to the .INI files.
But of course something really unusual might have happened, like a power loss or fluctuation *exactly* while an installer or GSX itself was writing that file, in that case a corruption could be possible, although it's an extremely rare chance.
I renamed it and ran again FSX, the file was rebuilt and the buildings appeared again.
Yes, that's to be expected. That file simply stores default for all Couatl addons, it can be safely removed, just that every general setting, like redefinable hotkeys, will go back to default.