The reason nobody has replied is that a search for the same error comes up with the solution.
ERROR_GEN_ZLIB_2 is related to having textures that are too big. So the ymap you load does contain big textures. (and zlib can’t compress them).
For more information:
The information above was found by this post;
So thank him for coming up with the solution and I guess you can give me a little thanks for finding the post.
My server has been experiencing the issue because of a resource that is on this forum called “LA Billboards”. Some of the billboards images are too large and causes the crash so if you have that installed I would recommend removing it unless you want to go through thousands of files downsize them.