Having run this with a debugger, I am getting a strange error indicating memory corruption, so I am running it again with Valgrind to see what the origin of the problem is. I should again be grateful if people could attempt to connect to try to trigger the error.
Note: Because I am running this in Valgrind, I am afraid that the loading process will be much slower than normal. I am joining at present, so it may be several minutes before anyone else can join.
For reference, the backtrace was:
(gdb) backtrace
#0 __GI___libc_free (mem=0x800030300) at malloc.c:2951
#1 0x00000000004628a9 in strasse_t::~strasse_t() ()
#2 0x000000000046bb26 in objlist_t::~objlist_t() ()
#3 0x00000000004517e0 in boden_t::~boden_t() ()
#4 0x00000000006dcf17 in planquadrat_t::~planquadrat_t() ()
#5 0x0000000000718cc9 in karte_t::destroy() ()
#6 0x000000000072ce15 in karte_t::load(loadsave_t*) ()
#7 0x000000000073067e in karte_t::load(char const*) ()
#8 0x00000000005a385e in nwc_sync_t::do_command(karte_t*) ()
#9 0x0000000000725ae2 in karte_t::do_network_world_command(network_world_command_t*) ()
#10 0x000000000072618b in karte_t::process_network_commands(int*) ()
#11 0x000000000073d06f in karte_t::interactive(unsigned int) ()
#12 0x00000000006cd6c2 in simu_main(int, char**) ()
#13 0x00000000006e1807 in sysmain(int, char**) ()
#14 0x00007ffff6b45830 in __libc_start_main (main=0x40efb0 <main>, argc=21, argv=0x7fffffffe458, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>,
stack_end=0x7fffffffe448) at ../csu/libc-start.c:291
#15 0x000000000040f019 in _start ()
Edit: I have had to restart Valgrind because there were so many errors (mostly in code from Standard, particularly the image node reader) that Valgrind refused to display any further errors before the occasion of the crash arose, so I had to disable the error number limit, which required restarting Valgrind. I anticipate that it will be 15-20 minutes before it will be possible for anyone to join.