Piggybacking this thread as I am experiencing the same issue
Using FSX with GSX & Level 2
All was working fine for me yesterday but today updated using FSDT Live Update (as prompted in the sim)
After the update I am no longer able to complete the boarding process when using a passenger airliner. I have tried both default and addon planes which were loading normally prior to the update. All of the airliners had GSX configs that had previously functioned with success, none of these configs were changed after the update. The passenger airlines tested were the Aerosoft Airbus A320, PMDG 737-800 and the default FSX 737-800.
No errors occured when using a cargo version of the FSX default 747-400, issue seems to be only related to boarding passengers.
I was able to load catering with no problem.
The issue happend both when using a jetway as well as using a gate with double stairs and no jetways.
Cargo loading belt vehicles move into position, the cargo loader dismounts his vehicle and begins to walk to the end of the belt and position to load baggage. At this point Couatl sends an error message with an error log option and asks to restart Couatl.
Problem persists at various airports, all airports are default scenery. I have only included the messages from KDAL, but each other airport was the same error code tracebacks just with different airport ICAO coes, gate numbers and respective position coordinates.
Same error message as the OP:
Erorr message when boarding passengers via jetway gate
couatl v3.2 (build 4477)
panic log started on Tue Sep 7 23:36:31 2021
problem raised by addon <unknown>
Traceback (most recent call last):
File ".\common\walker.py", line 113, in _observer
File ".\common\walker.py", line 231, in _advanceWalk
AttributeError: 'SimObject' object has no attribute 'destroyed'
{'Airport': 'KDAL', 'Requested assistance services at': 'Gate G 3', 'User Pos': (32.845073932617254, -96.85250911529404, 152.935 m, 4.49835 m, 91.61073015963423)}
Error message when boarding passengers at non-jetway gate
couatl v3.2 (build 4477)
panic log started on Tue Sep 7 23:37:56 2021
problem raised by engine or unspecified addon
{'Airport': 'KDAL', 'Requested assistance services at': 'Gate G 5', 'User Pos': (32.84665212035915, -96.8524829491091, 152.935 m, 4.49836 m, 92.60081494386888)}
Traceback (most recent call last):
File ".\common\walker.py", line 113, in _observer
File ".\common\walker.py", line 231, in _advanceWalk
AttributeError: 'SimObject' object has no attribute 'destroyed'
{'Airport': 'KDAL', 'Requested assistance services at': 'Gate G 5', 'User Pos': (32.84665212035915, -96.8524829491091, 152.935 m, 4.49836 m, 92.60081494386888)}