After upgrade FTP “Connexion information need it.”

I have a bit weird issue, while I installed manually my wordpress and I used root account, now It seems that I can login with another user but that user doesnt have root rights, and is not root. You think If I change the user permission and give it to root rights, would that be solved, with this username i can`t update anything while I receive permission errors like this:

Downloading update from http://downloads.wordpress.org/plugin/wp-maintenance-mode.zip…

Unpacking the update…

Could not create directory. /srv/www/plev.eu/public_html/wp-content/upgrade/wp-maintenance-mode.tmp

I am sure if il update manually to server from root account would work. What you suggest is the best way to solve the issue. I have to mention that before the upgrade I never had been asked about ftp credentials, and I had no ftp client installed. but worked fine. How I do not know.