Enfold 3 Errors: White space, Line 42 and http image erro

When I install the theme Enfold on my site the following error appears at the top of the page: Warning: session_start(): open(/var/lib/php-cgi/session/sess_n1bhut7m0e9ucg50t0bg86r9c7, O_RDWR) failed: No such file or directory (2) in /home/storage/5/00/79/qms/public_html/wp-content/themes/enfold/config-templatebuilder/avia-shortcodes/masonry_entries.php on line 42

And then, I can not upload any image that gives HTTP error.

Finally, instead of the Main Menu, there is a huge white space.