diff --git a/prebuild.xml b/prebuild.xml
index 407b986b8a..e4bbda3f0a 100644
--- a/prebuild.xml
+++ b/prebuild.xml
@@ -2682,6 +2682,7 @@
 
       <ReferencePath>../../../../../bin/</ReferencePath>
       <Reference name="System"/>
+      <Reference name="System.Xml"/>
       <Reference name="log4net.dll"/>
       <Reference name="Nini.dll" />
       <Reference name="nunit.framework.dll" />