Package: Magma Conduits
The mod had crashed when loading the world. The debug text mentions volcanoes.lua:126:attempt to call field 'parse_lines'(a nil value). Traceback goes to volcanoes.lua:126: in main chunk.
Do you have the latest version of name_generator (https://content.minetest.net/packages/FaceDeer/name_generator/) installed? That line is only called when name_generator is installed.