When I export my map and someone plays my map he go an error: 'Failed to create resource (is the file missing?): levels/terrain5.ter'. I copied all my files from documents/beamng/levels to Documents/BeamNG/mods/map. This is the second time that this happends. 0.9 update? (because it don't generate .ter files)
As it says, it's looking for 'terrain5.ter' in the levels folder (not in your levels) folder. Make sure that file is inside your level folder, and manually edit the main.level.json file so that the terrainblock path indicates your level folder, not just 'levels'.