The errors seems different, but they are probably caused by the similar issues: the scenery AFCAD surely must have problems/errors, like overlapping nodes, orphaned parkings, unreachable nodes, paths not connecting correctly, etc.
Can't say for sure without checking the scenery and without knowing exactly the gate used.
You might try to fix this, using the "Custom Pushback" option in the parking customization dialog, which will require to open the scenery AFCAD with ADE, and note the coordinates of a suitable node for the pushback.
You might want to contact the scenery developers, because it really looks that scenery needs some fixing. If you run it through the "Fault Finder" option in ADE, it's likely many errors will be reported.
