There is an art folder in the main root folder of BeamingNG. Check the terrains in there to see if there is a folder with the name of your level. Sometimes when you create a new ground plane it sticks it in there. That needs to be moved to your level folder if it is in there, along with everything else in that folder if it exists.
Yes, first a bunch of errors followed by a gigantic loud bang of the car exploding in some visual sand.