diff --git a/prebuild.xml b/prebuild.xml
index 0e5879272e..2b8e9634e0 100644
--- a/prebuild.xml
+++ b/prebuild.xml
@@ -3387,6 +3387,7 @@
 
       <ReferencePath>../../../bin/</ReferencePath>
       <Reference name="System"/>
+      <Reference name="System.Core"/>
       <Reference name="System.Xml"/>
       <Reference name="OpenSim.Framework"/>
       <Reference name="OpenSim.Framework.Communications"/>