diff --git a/OpenSim/Region/ScriptEngine/DotNetEngine/Compiler/Server_API/LSL_BuiltIn_Commands.cs b/OpenSim/Region/ScriptEngine/DotNetEngine/Compiler/Server_API/LSL_BuiltIn_Commands.cs
index 20f5d51280..eb72d5cf22 100644
--- a/OpenSim/Region/ScriptEngine/DotNetEngine/Compiler/Server_API/LSL_BuiltIn_Commands.cs
+++ b/OpenSim/Region/ScriptEngine/DotNetEngine/Compiler/Server_API/LSL_BuiltIn_Commands.cs
@@ -1,3 +1,4 @@
+using Axiom.Math;
 using System;
 using System.Collections.Generic;
 using System.Text;
diff --git a/prebuild.xml b/prebuild.xml
index db80a16ad3..69bea40743 100644
--- a/prebuild.xml
+++ b/prebuild.xml
@@ -941,6 +941,7 @@
       <Reference name="OpenSim.Framework"/>
       <Reference name="OpenSim.Framework.Console"/>
       <Reference name="OpenSim.Region.ScriptEngine.Common"/>
+      <Reference name="Axiom.MathLib.dll" localCopy="false"/>
       <Files>
         <Match pattern="*.cs" recurse="true"/>
       </Files>