diff --git a/prebuild.xml b/prebuild.xml
index af72eb52d2..6803cbd227 100644
--- a/prebuild.xml
+++ b/prebuild.xml
@@ -2685,6 +2685,7 @@
 
       <ReferencePath>../../../../bin/</ReferencePath>
       <Reference name="System"/>
+      <Reference name="System.Xml"/>
       <Reference name="log4net.dll"/>
       <Reference name="Nini.dll" />
       <Reference name="nunit.framework.dll" />