Hello Paolo
Can you send me upload your site to server and semd me joomla administrator via contact form? So we can help you
Or
Please help me find and open file:
modules\mod_jo_facebookevents\elements\loginfb.php go to line 25, 102, 132 and change to (remove tag &)
$db=JFactory::getDBO();
modules\mod_jo_facebookevents\elements\color.php go to line 25 and change to (remove tag &)
$document = JFactory::getDocument();
modules\mod_jo_facebookevents\tmpl\default.php go to line 62 and add tag @ before line
if(@$fbevent["end_time"] !=""){
Best regards
Bach Pham