When using the most recent sourceforge build, 6.10, and using the settings doom2 as the game and legacy for the engine. When I create a map, reguardless of size or number of levels it errors using the legacy engine settings. What do I mean by erroring? Well, when I load the created .wad file into chocolate doom, doom 2 within dosbox or native doom 2 version 1.9 on native hardware (pentium mmx 188mhz and ms-dos 6.22) it either fails with the error P_spawnmapthing: Unknown type 4000 at (2354,453), the coordinates and item number really don't matter, what matters is that under oblige version 6.10 using legacy settings the map is unplayable. Yet if I revert back to 4.28 it seems to load the map fine. Furthermore if I use version 4.28 and up all the way to 6.05 it creates the map just fine and it is playable, if you keep the level diversity and amount of monsters within the limits of original doom1 and doom2.