Mine has exactly the same problem - I know that doesn't help but at least you're not alone. I can't really think what would stop it spinning up; our has always been unbalanced during a fast spin and on testing it with nothing in or a small load it will spin up. So it seems to be the load or wonky spin that is stopping it.
Our door gasket is knackered too and has been since installation i think.
Mr D
September 2008