Lets say it's
possible this is due to a mismatch between the map and scripts. It depends a lot on how the server is set up, but I've seen some very fragile terrain-related code in this support forum over the last month or two
AFAIK each tile is just an item placed at the specified position. There are examples of them being changed in tiles.lua, snow,lua, decay.lua etc. You can instantiate a Tile object by specifying a location, and then perform various operations on it (check what's stacked on it, ask if it's PZ, etc)
The point is that it's not difficult to interact with the in-game map in Lua. Which means it's technically possible to try Tile operations at an invalid location.I can't know if you have some shaky code on your server, but it's easy to check.
Your error messages are highly suspicious because one of the coordinates is 64K. My guess is that some Lua code is trying to make a new Tile object there, and it's using an invalid x-coordinate. It could be -1, some number much larger than 64K, or exactly 64K (this would depend on how type conversions are handled between Lua and C++, and it probably wouldn't help to know). I have no idea what might generate this kind of error, nor if it might be induced by changing a map, but IMO it's worth checking anyway.
Your best option is probably to look for relevant Lua messages in your OT log and post them here.
If there are no Lua messages, second-best is to search the
/data directory for uses of the Tile object (search for "Tile:new(" and "Tile.new(" ), identify any customized scripts that contain either string, and check if they could be using crazy numbers.
To search quickly: download Notepad++ from SourceForge if you don't already have it, and then use Search/Find in Files/ and specify a directory search. It takes about 60 seconds on my PC to search all of TFS 1.0's scripts, and there's a nice panel you can use to check which files contain the search string.