I am still working on this problem,
Even with HHVM and Nginx I could not solve the problem,
I used solutions on this page and a dozen of other pages,
I can install Wordpress or other CMS with my server configuration,
with Nginx+HHVM or Nginx+fpm, or Apache2+normal PHP
but prestashop default db_structure.sql is not compatible with
mysql 5.6 + Nginx + HHVM or fpm !!!
when I wrote: sudo mysql_install_db
I had this error and warning:
Installing MySQL system tables...2016-04-09 14:17:53 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details).
2016-04-09 14:17:53 0 [Note] /usr/sbin/mysqld (mysqld 5.6.28-0ubuntu0.15.10.1) starting as process 24725 ...
//--------------------------------------------------------------------
Finally I found the origin of the problem on this page:
http://dev.mysql.com/doc/refman/5.6/en/upgrading-from-previous-series.html
by setting
explicit_defaults_for_timestamp = 1 in your my.cnf [mysqld] section I could get rid of the error and after restarting mysql (sudo service mysql restart)
I could get this:
Installing MySQL system tables...2016-04-09 14:32:10 0 [Note] /usr/sbin/mysqld (mysqld 5.6.28-0ubuntu0.15.10.1) starting as process 25189 ...
But still working on the problem, and I will let you know if I solve it
At least I know what causes the problem !
SOLVED + BUG REPORT!!!
I finally managed to solve the problem with reinstalling a new ubuntu 14.01 LTS on the server,
and MYSQL 5.5, and the rest is almost like this site:
http://websensei.uk/tip/view/install-prestashop-ubuntu-14-mariadb-and-nginx.html
I can install it with HHVM too, the problem was with mysql5.6 and its new configuration as described on their page:
Finally I found the origin of the problem on this page:
http://dev.mysql.com/doc/refman/5.6/en/upgrading-from-previous-series.html
************* so there are conflict on mysql5.6 + *********** new release of Prestashop 1.64
on Nginx as the web server! I have checked it works fine with apache2 but not Nginx with
Neither HVVM nor FPM