High over the ocean, drifting through a perfectly dappled blue sky, a colossal orange peach floats serenely on its way to New York, its ''crew'' a young orphan and his oversize insect friends. Coproduced by Tim Burton, this animated adaptation of Roald Dahl's 1961 classic evokes the casual enchantment of a book that, for many kids, cast the spell of a goofily blissed-out mirage. The sculpted animated figures really come alive, with the querulous insects emerging as funny, foibled characters. Unfortunately, the delicately beautiful stop-motion animation is framed by crude live-action scenes that effectively douse the spell. B