Material issue - I think it's trying to revert to an original png but not finding it.
WARNING: core/io/resource_format_binary.cpp:1094 - 'res://addons/verlet_rope_4_gd/materials/rope_default.material': In external resource #0, invalid UID: 'uid://b2hhc7qwdpqo1' - using text path instead: 'res://boats/three-ply-rope.png'.
ERROR: Failed loading resource: res://boats/three-ply-rope.png. Make sure resources have been imported by opening the project in the editor at least once.