Session path unwritable or invalid cookie settings. Fix: Check that the /tmp or /cache folder is writable by the web server. Also, clear your browser cookies.
Yes, via the “Language Manager” plugin. However, out of the box, V3.1.0.9 supports only one language per installation. For multi-language sites, you need to install the official i18n extension. General Cms V3.1.0.9 Download