You can't create a colony if you are playing with the max number of civs? You do however still suffer the colony cost penalty! I always play with 18 civs, thanks for letting us know in the Civolpedia Firaxis! Nice to see that you can only experience the new expansion if you play a certain way. I love spending money on an expansion only to find out it is either bugged(see espionage) or something I can't use in my game! I usually don't play with diplo victory on, but if I want the AP I have to. I am sorry but this is just shamefull.

yes it is pretty stupid. I hope they release a DLL for the huge amount of civs in the game in a future patch.

There are modded DLL's on the forum as well. take a look in the costumization forum for more info.