diff --git a/prebuild.xml b/prebuild.xml
index 36eb27b062..18f5dfb42e 100644
--- a/prebuild.xml
+++ b/prebuild.xml
@@ -1713,6 +1713,7 @@
       <Reference name="Nini" path="../../../../../bin/"/>
       <Reference name="log4net" path="../../../../../bin/"/>
       <Reference name="Nini" path="../../../../../bin/"/>
+	  <Reference name="zlib.net" path="../../../../bin/"/>
 
       <Files>
         <Match pattern="*.cs" recurse="true">