Sorry for the delayed response on this. I just checked out your site and do see the Register button redirects to the home page. Looking at our code, when Virtuemart is enabled as the Registration component, we will try to redirect the user to:
index.php?option=com_virtuemart&view=user
If I enter that URL after your domain directly (not even clicking the Register button), I'm brought to the home page. So, it seems that there's a redirection in sh404SEF which is setup to go to the home page. Can you look at your sh404SEF redirection URLs, search for that string above, and see what it's setup to redirect too... or just force it to redirect the page you want it to go to?
Alternatively, we can help you add an Itemid to the registration URL which should make it work as well.. but that's a change you'd need to make with every update of the SCLogin module, so not an optimal solution.
I hope that helps get you started,
Alex