how do i fix my hoover 1200 new wave washer dryer?

I've recently had to replace the inner door section of my Hoover 1200 New Wave Washer Dryer, since then, each time I begin a cycle, I get the led flashing either E1,E2,E3 and the drum goes into a mad spin!!! If I open the door, shut it, and try again it sometimes begins a cycle, but then repeats its failure!! Any ideas anyone?????