You can play the papal states??? Many people have told me that they are unplayable as they need much modification to them, and many of the exsisting modifications do not work. You could try it, im not sure what would happen if you did though, also, im sure that the timurids and mongols are possible to play arent they???

Also, what computer tpye have you got, if you have an XP it should work, but if you have a vista, you might need to turn the UAC off...