diff --git a/prebuild.xml b/prebuild.xml
index a9ddd27f41..f685ee44be 100644
--- a/prebuild.xml
+++ b/prebuild.xml
@@ -3272,6 +3272,7 @@
 
       <ReferencePath>../../../bin/</ReferencePath>
       <Reference name="System"/>
+      <Reference name="System.Core"/>
       <Reference name="System.Xml"/>
       <Reference name="OpenSim.Framework"/>
       <Reference name="OpenSim.Framework.Communications"/>