This is part of the continuing effort by North Korea to get American involvement in negotiations. Presumably they are trying to play a kind of brinkmanship bargaining, trading limited cooperation on the matter of WOMD for food and money. Historically this has been a very successful tactic, but the world has changed, and it has always been clear that North Korea had no more intention of honoring its disarmament agreements than Hussein.
Unfortunately, North Korea is a much thornier problem than Iraq, given that there are some reports indicating that they may already possess crude nuclear weapons and long-range ballistic missiles. Even discounting those, South Korea is vulnerable to conventional forces. It's a tough problem and there are no easy answers.