I don't quite understand this statement. The only real premise I can see in my original comment is

suppose humanity one day developed the ability to create wormholes.

(Please feel free to correct me if you were in fact referring to some other premise.)

Wormholes are generally agreed to be a possible solution to Einstein's equations--they don't, in and of themselves, violate conservation of energy. The scenario I proposed above is a method for generating infinite energy if physics actually worked that way, but since I'm confident that it doesn't, the proposed scenario is almost certainly flawed in some way. I asked my question because I wasn't sure how it was flawed. Whatever the flaw is, however, I doubt it lies in the wormhole premise.

EDIT: Also see the replies from shminux and Squark.