‘Can’t find page’ when wp-admin/install.php

Ok, so I’m a wicked noob when it comes to running my own website. I tried installing WP 2.6, created database, changed the wp-config.php page exactly the way I was supposed to, uploaded it to my host, etc. I thought I was doing everything right, but when I went to my site and add the install bit to the end, I get a message saying sorry, can’t find that page.

I’m using laughing squid, which uses plesk. Any clues what I might be doing wrong?

Thanks!