Okay folks. This is hopefully my last post on this issue, but I think I have got it to work.
I noticed my province_texture folder was missing from the map/cache folder. It seemed to have got deleted in my various efforts to get this mod working (and RoA) and I do remember this playing a part once upon a time.
So this is what I did to get things working:
Uninstall the game.
Reinstall the game (This means a new province_texture folder in map/cache- mine was missing hence this step)
Then copy that province_texture folder in the map/cache folder and then paste it somewhere (desktop etc).
I'm using a Steam copy so I think it updates the game with all the official patches. If you're using the disc then I think you'll need to update the official patches it via the launcher.
Then Patch up the game to 2.36c.
Install the mod in the mod folder.
Rename the cache folder in the map folder to cache_vanilla.
Create a new cache folder (in the map folder) and copy the Province_textures folder you put by earlier into that folder.
Launch the game, select the mod in launcher and it should load.
Press Single Player - and it shouldn't crash as it was before....
And indeed it hasn't. I can select the countries available. As I am a bit of traditionalist I have selected Rome. And the game has loaded up all fine.
Sorry if I have been wasting everyone's time on this, if indeed anyone strolls past this thread these days. But hopefully the above will make sense for anyone new coming to this game. It's a fab if flawed game and I do hope one day Paradox make the sequel that seems to be so coveted (certainly by the fans on this forum). But I doubt they will anytime soon now they are going up into space.
But then who I am to presume.
Happy trials.