Maybe they alpha maped it out so it would never show?
you better have at least two sea zones in the map, just in case. But how ccan you not have any seazone if you are extending the vanilla map (if I understand correctly)?
I didn't think you personally modified them, but the AGOT team might have in order to block out winter (again, not sure). I would honestly just PM Knuckey and ask as he would likely know the answer off the top of his head.
the order of provinces doesn't matter but make double sure you dont have duplicate or missing numbers in the second column in the mapfiller. It's most likely coming from that.
Is your world_normal_height.bmp bigger then 3072 by 3072?
Maps larger then 3072 by 3072 still need to have the world_normal_height.bmp no larger then 3072 by 3072
But I imagine the normal map need to keep the original height/width ratio? How much can it be escalated down? Is e.g. 50% of the original area too much or too little?
The clausewitz mapchecker basically tells you if there is a color in provinces.bmp that is not defined as a province. That error does not cause crashes, as far as my experience goes, but only empty areas (like, say, the Sahara or the easternmost part of the map in vanilla.
Another question, have you recently modified terrain, topology, etc. ? an error in latest stages of loading can be caused by one of the map files that need to be indexed is saved without indexing.
Anyway, a general advice: when building a map from scratch I found useful to save backups of my files every so often, so that I can fall back to a safe version if something goes wrong.
If you efinitely cannot find the error, try downloading your files, yes. (I cannot test them myself, since for the time being I cannot access my gaming pc.