fixed chat (sql now returns NULL for max(id) instead of 0) and parseStringCritical (handover NULL)

ag/ag_popupchat.php

@@ -203,4 +203,4 @@ if (isset($_GET['send'])) {
 <?php
 
 	}
-?>
+?>

ag/include/parse.inc.php

@@ -303,6 +303,9 @@ function validateStringArray($value){
 }
 
 function validateStringCritical($value) {
+	if($value == null) {
+		return null;
+	}
 	$value = validateString($value);
 	return preg_replace('#[()\]\[\s]#', '', $value);
 }