Importing maps from GG is not 100% doable; since GGMax is in essence a different world.
GGMax lately is generating an LST file i.e.
mymap.frm and
mymap.lst.
The lst file list all the stuff you have in your map; since the GG map does not have that, so, GGMax has nothing to list your map stuff and crash, just guessing here. Although GGMax should deal with, rather than crash.
Does all your stuff are located on
entitybank>your folder? I ask because if any of that meshes is not in the folder, GGMax most likely will crash.
Remove all the GG DBO files, GGMax will generate new ones, when converting meshes to the GGMax system.
And if those do not work, so, you can zip the frm file, and there you can get the meshes listed, that your map has, so, you can check if you have all those stuff already, in your entitybank>your folder.
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