I've noticed on several cup holders from those year models that they get gummed up. Take the time to clean the tracks every now and then and they should slide nicely for years to come.
Knock on wood, mine works like new. Could be from me NEVER using it.
Crap I almost forgot! If they get stuck just access it from the glove box. You should be able to get your hand in there behind it and push it loose.