[Mobhack]

The only thing that makes the game crash is "foreign" characters, not in the standard ASCII set. So umlauts, cedillas etc. This is mentioned in the game guide and Mobhack help as a no-no.

These could be in the unit names, the leader names files etc - depending on what you changed.

So open Up Mobhack and change the names for all your new units, formations, weapons to a default for testing - e.g. A for the first, B C etc. Then try again, it may pass the point where it crashed. If so - it was your names used for whatever (unit, formation, weapon). Then go back and put in standard ASCII names e.g. Bluecher not Blucher (with an umlaut).