diff --git a/fp-includes/core/core.bplustree.class.php b/fp-includes/core/core.bplustree.class.php
index 53d0a0b..895ab67 100755
--- a/fp-includes/core/core.bplustree.class.php
+++ b/fp-includes/core/core.bplustree.class.php
@@ -138,11 +138,11 @@ define('NOROOMERROR', -100);
 /**
  * @const int null node
  */
-define('BPT_NULL', -1);
+define('BPT_NULL', 0);
 /**
  * @const int null seek position
  */
-define('BPT_NULLSEEK', -1);
+define('BPT_NULLSEEK', 0);
 /**
  * @const string magic string for bplustree
  */