change line 23:
$WAFV_Errors .= WAValidateDT(((isset($_POST["eventoFINE"]))?$_POST["eventoFINE"]:"") . "",true,".*","".((isset($_POST["eventoDATA"]))?$_POST["eventoDATA"]:"") ."","".((isset($_POST["eventoDATA"]))?date("m/d/Y",*mktime(0,0,0,date("m",strtotime($_POST["eventoDATA"])),date("d",strtotime($_POST["eventoDATA"]))+5,date("Y",strtotime($_POST["eventoDATA"])))):"");* ."",false,".*","","",true,5);
to:
$WAFV_Errors .= WAValidateDT(((isset($_POST["eventoFINE"]))?$_POST["eventoFINE"]:"") . "",true,".*","".((isset($_POST["eventoDATA"]))?$_POST["eventoDATA"]:"") ."","".((isset($_POST["eventoDATA"]))?date("m/d/Y", mktime(0,0,0,date("m",strtotime($_POST["eventoDATA"])),date("d",strtotime($_POST["eventoDATA"]))+5,date("Y",strtotime($_POST["eventoDATA"])))):"") ."",false,".*","","",true,5);