Installed WordPress – site not working

Hi all.

I hope you can help! I have installed WordPress in the subfolder http://www.mysite.dk/wordpress and the admin module is working fine. But when I want to visit the site http://www.mysite.dk/wordpress I get either 1: error message (Explorer)
2: A page showing “:(” (Google Chrome)
3: redirect to original site but with the adress http://www.wordpress.mysite.dk (on my Ipad)

What is wrong? I want to keep the original site while I develop the new site.