I'm sorry to hear of your problems with Sequel. Can you launch the app at all, and, if so, what exactly isn't working right? Also, on what kind of machine have you installed it?
As mentioned in the Conclusions, I did run into a few issues with Sequel, some of which, admittedly, were rather annoying. However, overall, the software worked just fine on my test machine, an Apple MacBook with a 2GHz Core 2 Duo processor and 2 Gigs of RAM, running Mac OS X 10.4.
Have you contacted Steinberg directly via their Support Request Form (http://www.steinberg.net/290+M52087573ab0.html) , or gotten in touch with the distributor (http://www.steinberg.net/283+M52087573ab0.html) for your region for official support?