Getting Fatal Error when trying to run install.php

Hi,

I’m new to WordPress and I’m trying to install it on my domain. I keep getting the following error when running install.php:

Fatal error: Call to undefined function is_admin() in /home/lennuk/public_html/georgescarblog/wp-admin/includes/comment.php on line 110

I’ve tried three different methods: 1) download to SSH and unpack there. 2) download to my PC, upload to server and unpack with SSH 3) Upload all the files separately from my PC and run the install.php

They have all given the exact same error. Is there a possibility that the current downloadable version could be buggy?

Thanks for your help!