Can't upload language in administrator folder

[Jan]

try to use some web based file manager

[thijeleo]

On some direct-access sites you can login to the access-manager through http://www.yourdomain.ext:2222

If this works you can login and use the filemanager from the menu you will see after login. With this filemaneger you can reset the ownership.

If you don't have this possibility, you can ask your hoster to reset the ownership.