Well, i also created some nations, in the 10.3, and they worked well during season 1, where they only make friendly matches, then they worked well in the second season, also only friendly matches, but more or less between the end of season 2 and beginning of season 3, the game crashes.
What i know is that the game advances with no problems, if i do not use the extra nations, but crashes with them on. (no nation rules applied, i just created the new nations, nothing more....)