Problem setting up a codeigniter-project on webserver

Hi

I have a codeigniter-project that I've been developing via my own computer with MAMP-server.
Now I am trying to move this project to a webserver under a subfolder.
When I upload the files and try to open the first screen, I get a 404 error.

Strange thing is that if I upload a clean codeigniter installation under another subfolder to the same server the project opens correctly with a welcome screen. So the server itself should be ok.

Thank
pg betflik