Open the door and remove all the screws holding the front panel in place. After carefully removing the front panel. inspect the latch and handle assembly for any jamming. The latch assembly is held in place by the screws you just removed. Note that the handles attachment to the front panel is stupidly weak and if it hasn't failed yet (like mine has), it may well have a broken attachment piece blocking the full operation of the handle. Parts to replace the front panel and handle seem to be around $60 (US). You should be able to remove the handle and still be able to operate the door (without a butter knife). This is how I am using my dishwasher right now.
Bill Clark, November 2007