Sorry, no prizes for guessing this one.
E07 indicates Defective Door Safety Lock Device (blocked closed) and/or Wiring.
If you unplug the appliance from the wall socket does it unlock then?
If not, I'm afraid it's a case of unplugging the appliance and taking the top off.
Reach down the front until you come to the door lock.
Try to see if you can unlock it by "waggling" it about.
If you can't, you'll need to work it back and forth, side to side until it comes off of it's screws.
Once off, lift it off the door latch.
You will of course have to replace the door lock.
Hope this is of some help
Let me know how it goes or if you need more help.