From a post to Baen's Bar BuShips dated January 18, 2002:

Drive field requirement for warp transit

    They don't need a magic drive to make transit; they need a sufficiently powerful drive field to survive making transit. There's a difference. You can put anything you want through a warp point; it's just that it tends to come out rather finely subdivided on the other side if the drive field hiccups during the process.