diff --git a/OpenSim/Region/ScriptEngine/Shared/LSL_Types.cs b/OpenSim/Region/ScriptEngine/Shared/LSL_Types.cs
index 212dbe3a1b..59279735f0 100644
--- a/OpenSim/Region/ScriptEngine/Shared/LSL_Types.cs
+++ b/OpenSim/Region/ScriptEngine/Shared/LSL_Types.cs
@@ -663,13 +663,13 @@ namespace OpenSim.Region.ScriptEngine.Shared
                 Object[] ret;
 
                 if (start < 0)
-                    start=m_data.Length-start;
+                    start=m_data.Length+start;
 
                 if (start < 0)
                     start=0;
 
                 if (end < 0)
-                    end=m_data.Length-end;
+                    end=m_data.Length+end;
                 if (end < 0)
                     end=0;