Problems setting up a RoR server

Hi, I'm trying to launch my new RoR site but I've some problems with my server. On the the test server of my website developer everything works just great but not on my official VPS. This is the link to the test server http://first-link.digiti.be, and if you than click for instance if you click on Administratie on the left menu and then on Database Entry it will go to http://first-link.digiti.be/nl/administratie/database_entry . But if you do the same thing on my VPS (http://beta.first-link.be) it will go to http://beta.first-link.be/firstlink/public/nl/administratie/database_entry , so it adds /firstlink/public which I do not want.

These are the specs of my VPS: Fedora Core 6 PLESK 8.3 Apache

If you need more information just ask.

Thank for your help.