diff --git a/prebuild.xml b/prebuild.xml
index 6b2579248e..fd714755fb 100644
--- a/prebuild.xml
+++ b/prebuild.xml
@@ -157,6 +157,7 @@
       <Reference name="System.Xml"/>
       <Reference name="System.Data"/>
       <Reference name="System.Drawing"/>
+      <Reference name="System.Web"/>
       <Reference name="BclExtras.dll"/>
       <Reference name="OpenMetaverseTypes.dll"/>
       <Reference name="OpenMetaverse.dll"/>