This is really weird. I created a colony from barbarian cities and after doing so I declared war on half the world? Is this a bug or something?

This is a known bug introduced in BTS version 3.13 that occurs if you create a colony in a game with 18 or more civs. A thread that discusses it is:
http://forums.civfanatics.com/showthread.php?t=264185

Bhuric's unofficial patch addresses that issue. It can be found on this forum at:

http://forums.civfanatics.com/showthread.php?t=246057

ohhhh tnx so much