I was playing as the Spanish, afetr I got Independence, I got a message that said "Danger Will Robinson! Poor Defenses 72920 (or something like that)." Anyone else get this? And is it a joke or bug or whatever?

I've never seen it myself. Didi it include an action or was it just this message?

In old games like Colonization they tent to include some hidden joke sometimes, so it is conceivable. ;)

I seem to remember seeing this in the debug.txt, so yes, there must have been an internal error of some sort.