Merge pull request #21 from EngineGPDev/Deprecated-preg_match()-Passing-null-to-parameter-#2-($subject)-of-type-string-is-deprecated-in-/enginegp/system/library/acpsystem.php-on-line-105

Deprecated: preg_match(): Passing null to parameter #2 ($subject) of type string is deprecated in /enginegp/system/library/acpsystem.php on line 105

system/library/acpsystem.php

@@ -75,6 +75,7 @@
 
         public static function valid($val, $type, $preg = '')
         {
+            $val = isset($val) ? $val : '';
             switch($type)
             {
                 case 'promo':