Alright, after a long hiatus (front line worker and all that) I've had a chance to play with this some more. Sadly, even after 9 (NINE!) re-installations including the above linked client, I still cannot extract the correct maps/vmaps to run the mangosd server.
As mentioned, I've had no issues at all with two, and have run it since 2016. Three however is being difficult and since I have a bit of time I thought I'd bash at it. It does not complete the extraction process straight off the install. It always fails after extracting the dbc files. However, manually copying the tools over to the client folder and running ExtractResources.sh works. I then copy over the files to the mangos three install and every time it fails with the 0004331.map file error. I've tried 6 different clients including the one linked above. So it seems either the tools or the clients are bad.
I'm wondering, does it have to be a client that's been played and thus loaded into cache some of the new areas? (This I have not done, as I've not wanted to play on a random private server to get the files substantiated.) Alternatively, does ANYONE have the maps/vmpas/mmaps for 4.3.4 that work with Three? I'm frustrated as hell here.
Running it on a CentOS7 server btw. The guide works perfectly for everything but the extraction. And as mentioned, I've had two running for years. (Hence the interest in playing with three for a change.) I refuse to go to another distro for the server as Mangos is where I cut my teeth on this stuff many years ago. Strangely enough, back in what... 2012(?!!) 4.3.4 is the server I first had running!