Hi,
This website is full of PHP errors. Make sure you are using a correct server to support Joomla properly.
On this page:
www.univershop21.es/index.php?option=com_virtuemart
I am seeing this Error message:
Warning: file_exists(): open_basedir restriction in effect. File(/) is not within the allowed path(s): (/home/univershop21:/home2/univershop21:/usr/lib/php:/usr/local/lib/php:/usr/local/php7:/usr/local/php55:/usr/local/php54:/usr/local/php53:/usr/local/php52:/tmp) in /home/univershop21/public_html/libraries/joomla/filesystem/file.php on line 392
which is not okay.
To fix this problem:
Notice: Undefined variable: checkAutomaticP in /home/univershop21/public_html/modules/mod_flexible_vm3_cart/mod_flexible_vm3_cart.php on line 75
Open this PHP file:
/modules/mod_flexible_vm3_cart/mod_flexible_vm3_cart.php
find this line:
$data=$plg->prepareAjaxData($checkAutomaticP);
and replace it with this:
$data=$plg->prepareAjaxData($checkAutomaticPS);
and this error will be gone.
Alternatively, i recommend you to set the "Error Reporting" to 'NONE" via Joomla Global Configuration.
Regards.