2016-06-14 03:28:56: ERROR[main]: UNRECOVERABLE error occurred. Stopping server. Please fix the following error:
2016-06-14 03:28:56: ERROR[main]: Lua: Runtime error from mod '*builtin*' in callback on_newplayer(): /usr/share/games/minetest/builtin/common/misc_helpers.lua:525: attempt to concatenate local 'y' (a nil value)
2016-06-14 03:28:56: ERROR[main]: stack traceback:
2016-06-14 03:28:56: ERROR[main]: 	/usr/share/games/minetest/builtin/common/misc_helpers.lua:525: in function 'pos_to_string'
2016-06-14 03:28:56: ERROR[main]: 	/usr/share/games/minetest/builtin/game/static_spawn.lua:21: in function 'put_player_in_spawn'
2016-06-14 03:28:56: ERROR[main]: 	/usr/share/games/minetest/builtin/game/static_spawn.lua:27: in function </usr/share/games/minetest/builtin/game/static_spawn.lua:26>
2016-06-14 03:28:56: ERROR[main]: 	/usr/share/games/minetest/builtin/game/register.lua:355: in function </usr/share/games/minetest/builtin/game/register.lua:335>

In thread 7f5a09194780:
/build/minetest-6sh_iU/minetest-0.4.13+repack/src/server.cpp:511: void Server::step(float): A fatal error occurred: Lua: Runtime error from mod '*builtin*' in callback on_newplayer(): /usr/share/games/minetest/builtin/common/misc_helpers.lua:525: attempt to concatenate local 'y' (a nil value)
stack traceback:
	/usr/share/games/minetest/builtin/common/misc_helpers.lua:525: in function 'pos_to_string'
	/usr/share/games/minetest/builtin/game/static_spawn.lua:21: in function 'put_player_in_spawn'
	/usr/share/games/minetest/builtin/game/static_spawn.lua:27: in function </usr/share/games/minetest/builtin/game/static_spawn.lua:26>
	/usr/share/games/minetest/builtin/game/register.lua:355: in function </usr/share/games/minetest/builtin/game/register.lua:335>
Debug stacks:
DEBUG STACK FOR THREAD 7f59f3fff700:
#0  virtual void* EmergeThread::Thread()
(Leftover data: #1  MapBlock* ServerMap::loadBlock(v3s16))
(Leftover data: #2  void ServerMap::loadBlock(std::__cxx11::string*, v3s16, MapSector*, bool))
DEBUG STACK FOR THREAD 7f5a00c21700:
#0  virtual void* CurlFetchThread::Thread()
DEBUG STACK FOR THREAD 7f5a01422700:
#0  virtual void* ServerThread::Thread()
#1  void Server::Receive()
(Leftover data: #2  void Server::SendBlocks(float))
(Leftover data: #3  void RemoteClient::GetNextBlocks(ServerEnvironment*, EmergeManager*, float, std::vector<PrioritySortedBlockTransfer>&))
(Leftover data: #4  void ItemStack::serialize(std::ostream&) const)
(Leftover data: #5  bool getCraftingResult(Inventory*, ItemStack&, std::vector<ItemStack>&, bool, IGameDef*))
DEBUG STACK FOR THREAD 7f5a09194780:
#0  int main(int, char**)
#1  Dedicated server branch
#2  void dedicated_server_loop(Server&, bool&)
#3  void Server::step(float)
Aborted