Just in case anyone else is following this thread, I just got an email back from the Atkins Center. They say I ordered the vitamins in February 2002 (one year prior to the expiration date). They said that since they were more than 6 months past the expiration date, I should discard them.

My fault. When I received the vitamins, I should have looked at the expiration date and determined whether I would have used them up within a year.

Live and learn. Guess I'll toss 'em.