There is only a 2MM gap between the door and the ground. Make sure that the ground the printer is laying on is flat and even. If you are on a flat surface, then turn the printer off and on, and let the print head adjust to its home position on the left hand side. If the print head if not in the home position, it essentially acts like a lock.
If you still cannot open the printer then we suggest calling DNP or Imaging Spectrum.
If you are at an event and it can't open then we wouldn't suggest forcing anything since it might damage the printer further. You can always print the images after the event and mail them to the client. It's a lot cheaper to apologize and mail prints rather than having to replace an entire printer!