Well we do not know if it is something wrong with your host or that the script does not work out for you at this moment. Please keep testing and lemme know what happens later tonight. I do not suppose it was hacked, otherwise Nemesis is doomed.
It seems that I can log in now, and the user profile indeed is not working. Does the table prefix_users_profile exist in your database? Just curious.
Edit: I installed the script on another server of mine, and it works flawlessly. The url is posted below, you can take a look yourself too. I am able to log in upon registration with however many alts I use. Would you mind contacting Nemesis for this? Perhaps he knows what is going on with the hosting service?
http://www.mysidiarpg.com/site/mys131/index.php