17:35:05: ERROR[main]: ServerError: /home/ulla/.minetest/mods/pipeworks/item_transport.lua:257: attempt to index a nil value
17:35:05: ERROR[main]: stack traceback:
17:35:05: ERROR[main]: 	/home/ulla/.minetest/mods/pipeworks/item_transport.lua:257: in function 'go_next'
17:35:05: ERROR[main]: 	/home/ulla/.minetest/mods/pipeworks/item_transport.lua:441: in function 'on_step'
17:35:05: ERROR[main]: 	/home/ulla/.minetest/mods/pipeworks/luaentity.lua:331: in function </home/ulla/.minetest/mods/pipeworks/luaentity.lua:308>
17:35:05: ERROR[main]: 	/usr/share/minetest/builtin/game/register.lua:348: in function </usr/share/minetest/builtin/game/register.lua:336>
17:35:05: ERROR[main]: ServerEnv: Trying to store id=7 statically but block (-101,-50,-27) already contains 49 objects. Forcing delete.
17:35:05: ERROR[main]: ServerEnv: Trying to store id=8 statically but block (-101,-50,-27) already contains 49 objects. Forcing delete.
17:35:05: ERROR[main]: ServerEnv: Trying to store id=9 statically but block (-101,-50,-27) already contains 49 objects. Forcing delete.
17:35:05: ERROR[main]: ServerEnv: Trying to store id=13 statically but block (-101,-50,-27) already contains 49 objects. Forcing delete.