You must change your virtual host configuration to provide access to the /tmp folder. This is done by manually adding a file into the “conf” directory located just next to the “httpdocs” folder containing your website. If you do not have access to the parent folder of the folder containing your website you cannot do it yourself.
If you can access to the “conf” directory, create a file named vhost.conf and upload it into the “conf” folder. The file should follow this pattern (please note that the path is an example and must be replaced by the path of your website directory) :
<Directory /var/www/vhosts/yourdomain/httpdocs>
<IfModule sapi_apache2.c>
php_admin_flag engine on
php_admin_flag safe_mode off
php_admin_value open_basedir “/var/www/vhosts/yourdomain.com/httpdocs:/tmp”
</IfModule>
<IfModule mod_php5.c>
php_admin_flag engine on
php_admin_flag safe_mode off
php_admin_value open_basedir “/var/www/vhosts/yourdomain.com/httpdocs:/tmp”
</IfModule>
</Directory>
Then connect via ssh to your server and apply this configuration by typing (this example is the command line I use with plesk installed):
/usr/local/psa/admin/sbin/websrvmng –reconfigure-vhost –vhost-name=yourdomain.com
Please note that I use my own server with plesk installed on it.
Hope this help …