Ah, in 2019 the link is already dead... More precisely, the map itself is missing from the link.

If anyone still has it, please upload the map here.

Yes, there are issues with 320x320 maps, ranging from significant slowdowns (although it's possible my computer is just too old) to excessively large save file sizes, which, as a result, cannot be loaded. While the map is still in its early stages, I would advise you to seriously consider switching to a smaller scale (you can try moving objects using Ctrl-C and Ctrl-V).

What does your computer have to do with it? I have 16 GB of RAM, and it still can't load a 5 MB map save . It's all about the game's optimization, which is as old as mammoth dung and was made by incompetent specialists. It's like with the Windows Photo Viewer program, which says Windows cannot display the image. There may not be enough free memory. Top-tier games run smoothly, but it needs a lot of memory for a kilobyte-sized image. To solve the problem, you need to download and install a separate icc CoatedFOGRA39.icc color profile. So, don't blame your PC (there are no PCs left that couldn't handle loading a save file) - it's all the fault of the inept programmers.
P.S. For information, in the Minecraft game, a player on the spigot forum boasted about his world save, which is 74 GB in size! Can you imagine how long it takes to unpack this file? And they say that this is not the limit. The size of my personal saves in the Skyrim game reached 80 MB, and nothing happened.