I solved it! Like always, had to do it myself.
I don't know what you are trying to say with "like always", but you surely couldn't expect 24/7 support during Christmas.
Run the GSX Level 2 Control Panel, Make sure default gateways is inactive and check every modified xml on the list and click the compile button.
No need to do that, of course. As the message said, you only had to enter the GSX Control Panel, and Disable the default jetways. No need to recompile the XML files.
The message appears because GSX checks the the default airport_objects.bgl file, which can be patched or unpatched. If the simulator was updated, the file reverted to the upatched status, so GSX will correctly stop to create its own jetways (otherwise you'll see double jetways default+GSX), and will correctly give you that message, so you'll know you must disable the default jetways.
So, what "fixed" it for you was to disable the default jetways, which is what the message told you to do.
Nothing in the status of the various XML/BGL exclude files could possibly affect this but, since you said you did both (disabling the default jetways and recompiling), you think you fixed that way, but you haven't. It was enough to disable default jetways, as the message said.
