I get this when trying to update:

Warning: file_put_contents(/home/internet/domains/internetkassa.nu/public_html/administrator/language/en-GB/en-GB.com_content.ini) [function.file-put-contents]: failed to open stream: Permission denied in /home/internet/domains/internetkassa.nu/public_html/libraries/joomla/filesystem/file.php on line 298
Failed to extract archive!

Hi Roderick,

you need to ensure that Joomla! can write to all files on your server it might want to update. Either change the permissions or try enabling FTP mode. Joomla! has to be able to write to the files otherwise it can't update them and you'll have to do it manually. Consult with your hosting provide on how best to achieve this,

Cheers,

Sam

I am my own hosting provider

All the needed files are set to 777 what other files should be set to 777?

You probably shouldn't set everything to 777, but that should be sufficient in the time being. If you aren't using suphp or similar then your PHP instance will be using the web servers account to write the files. If they aren't owned by the web server or writeable to it then you're going to have issues. I find personally that I set the web server to own the files and let Joomla! handle all interaction. This means that FTP/SSH stuff doesn't work properly (because you don't own the file, the web server does), however Joomla! works smoother.