diff --git a/src/codegen.inc.php b/src/codegen.inc.php
index eb5efa5..de0ede5 100644
--- a/src/codegen.inc.php
+++ b/src/codegen.inc.php
@@ -100,7 +100,7 @@ function apply_value_filters($field_name, array $tokens, $val, $add_assoc_check
     if(strpos($token, 'flt_') === false)
       continue;
 
-    $filter_func = 'mtg_' . $token; 
+    $filter_func = '\metagen_php\\' . $token; 
 
     if(function_exists($filter_func))
     {