diff --git a/prebuild.xml b/prebuild.xml
index 33267e24a9..9f64159682 100644
--- a/prebuild.xml
+++ b/prebuild.xml
@@ -122,6 +122,7 @@
       <Reference name="System.Xml"/>
       <Reference name="log4net.dll"/>
       <Reference name="OpenMetaverse.dll" />
+      <Reference name="OpenMetaverseTypes.dll"/>
       <Reference name="OpenSim.Framework"/>
 
       <Files>