Couatl crash

[airbadger]

Traceback (most recent call last):
  File ".\GSX\assistanceServices\pushBack.py", line 949, in walkAndDestroy
  File ".\common\walker.py", line 276, in walkTo
  File ".\common\walker.py", line 282, in _walkTo
AttributeError: 'NoneType' object has no attribute 'addMarkers'
{'Airport': 'KDEN', 'Requested assistance services at': 'Concourse B|Gate 24', 'User Pos': (39.85741389820024, -104.67769038549993, 1659.77 m, 4.39965 m, 90.64827424199304)}

[virtuali]

Please describe exactly what you were doing and all the usual things we always require to troubleshoot an error:

- the airport used. if it's not default, clearly identify the scenery

- the airplane used

- the precise, exact, sequence of operations you made in GSX.

- if you used a standard pushback or a custom pushback. If it was standard, which direction you chose. If it was custom, please provide with your GSX .INI customization for that airport, and indicate which custom pushback you chose, if there was more than one for that gate.