gekke-henkie
I don't think you should have used chmod, but chown. I think the files should be owned by the user running the webserver. With CentOS and apache (in my case) the user is apache, with group apache.
"when opening the extracted folder i get an error like this Root---- local.php already exjsts"
Uhh, without the exact error and/or what you did to get this far I don't think we can help much.