If your web server has register_globals turned on, then Drupal (5.x or later) won't install until you fix it. Unlike Drupal other free and open source CMS systems like Wordpress, Textpattern gives you a security warning, but installs without a squeak. Anyway don't fret over it much, it for your own good. (Detailed discussion about the the evil :P register_globals is posted here).
The solution which is commonly suggested is to try placing php_flag register_globals off line in your .htaccess file. If you are using Apache 2 server then you'll get a HTTP Error 500 Internal server error (like I had on the webserver that hosts my test server).You can try creating a php.ini with these lines and keep it your root folder of the website.
If nothing works then you can request the hosting company to make the changes to the global php.ini file nicely.