I'm playing your scenario with the latest IGC (2.2c) and pathc 1.09.
On my first game, it crashed while saving (and I forgot to run byzantium.exe...). No problem after that for a while.
Now, I'm in 1569, I get a conquistador and I send him to conquer the Incas; unfortunately on the 1st january 1570, the game crash. I disabled the autosave feature, but it still crashes to the desktop. There seems to be an event happening and I think it's a new monarch; however, I'm not sure since it goes by very fast.
In my last IGC game, I couldn't accept peace with either SPain or Russia. So, prior to running your scenario, I completely uninstall every thing EU on my computer, and then reinstall EU, the patch, IGC 2.2c (I had 2.2) and your Bizantium scenario.
Now, I can't get my game to work, any suggestion?
p.s. If I want to play another IGC, can I just run IGCconfig or do I need to reinstall it? Same for Bizance, after IGCconfig, can I simply run bizantium?
UPDATE: The event is the opening of a new center of trade somewhere. Don't know where 'cause it disapears too fast. I tried loading a older game and tried something different, but same result.