Hotseat Savegame Issue - Vista/Win7/Sega/Steam compatibility?

[HandKing]

Dear All;

I have just started my first 2 player (on seperate machines) hotseat. I've successfully started it, ended my turn, saved, then sent the save to the other player. They have succesfully downloaded it, played their turn, saved it, then sent it back.

Now; I download the save file and put it in my saves folder (also gave myself admin rights to it and "unblocked" it as it was from another computer), but when I load the game, it shows the loading screen with the year (no faction banner visible) and after a second or two, it then stops loading the save and switches to another loading screen that takes me back to the main menu.

I've checked the log file and found this error:

[version.registry] [error] File version (3) of <EVENT_DETAILS> is grater than latest version (2) !

The only related thread I found was this:
http://www.twcenter.net/forums/showthread.php?t=291016

Which *might* actually make sense...
I am on Vista (32bit), and the other player is on Windows 7 (64bit). So the issue could be Vista.

OK; so here are the questions I have;

1. Does your OS make any difference to the compatibility of hotseat games? (Has anyone successfully played hotseats across multiple OS's? - Vista especially)
2. Does your game publisher make any difference to the compatibility of hotseat games? (I'm on the purchased-from-the-shop-out-of-the-box Sega version, the other player has the Steam version)
3. Could this be an mtw2.preferences.config/tatw.config file setup issue? (Do they have to be exactly the same?)

Cheers in advance all!