Um, I don't know where you've gotten that; but it's totally bogus and false. Prince Caspian is being made, as confirmed by truthful sources found on NarniaFans.com. Prince Caspian is most certainly being released: May 16th, 2008. No worries.
Disney is making the film in ENGLAND not NEW ZEALAND. That's what the article is about. The switch was determined by England's willingness to waive applicable taxes, a last minute decision. I know this from the most reliable sources there are.