Depending on how big your database is, step 6 may be taking a while and the app hasn't actually frozen. It may be enough to just let it back up a while longer.
If you haven't already, I encourage you to email
omnifocus@omnigroup.com, so they can dig into the details of what's going on, and help you get going again.
Actually, you sound pretty stuck, so it may be better to email
urgent@omnigroup.com, since you can't really use OmniFocus at all until this is sorted out.