Couple of basic questions:
1. Who is your host?
2. Are you sure they offer PhP and MySQL?
3. Do they have PhPMyAdmin
4. Have you read the installation instructions?
http://bosi.allin1websolutions.com/help/help_index.php
If all of those are a yes, and your host isn't Yahoo, Lycos or PowWeb, or most free hosts (the hosts that I know of that can't run BOSI at the moment), then post specific questions, and I'll see what I can do.