I think that international credit rating agencies(especially Moody's) and foreign investors were spooked by constant discords between Mr. Roh and American gov. Wealthy people in S. Korea got spooked, too. Such a scare created many disturbing phenomena. The sudden popularity of dollar-denominated bank accounts among well-to-do folks. Talks of emigration via investment visas. People buying up gold. Foreign business execs bailing out, with two years still left in their leases, even though their lease agreement has no provision for any kind of refund. All these things must have made Mr. Roh really scared.
It was fun to watch some of his erstwhile die-hard constituency turning on him, basically branding him as a traitor over this flap.
It is clear that Mr. Roh saw this troop deployment as a sure way of redeeming his previous blunders, defusing the discord between two governments and apprehension among business folks. The big stick of Rummy, Safire, and Novak produced the intended results by spooking business atmosphere in S. Korea. Of course, it would also help to secure contracts for Iraqi reconstruction projects. But that is a minor consideration, though.
He is way behind the learning curve when it comes to international economy and national security.