diff --git a/build.xml b/build.xml
index d0555659ae..c819e242cb 100644
--- a/build.xml
+++ b/build.xml
@@ -981,18 +981,22 @@
 
     <target name="pack200">
         <!-- pack200 will only pack to a .pack file, and only from a .jar file, so we put another .jar on the end -->
+        <!-- can't pack an empty jar or one without classes, it will fail to unpack on Java 5;
+          -  see http://bugs.sun.com/view_bug.do?bug_id=6712743
+          -->
         <!-- *nix here -->
         <exec executable="sh" osfamily="unix" failonerror="true">
             <arg value="-c" />
-            <arg value="for i in pkg-temp/lib/*.jar pkg-temp/webapps/*war; do echo pack200 $i; mv $i $i.jar; pack200 -g $i.pack $i.jar; rm -f $i.jar; done" />
+            <arg value="for i in pkg-temp/lib/*.jar pkg-temp/webapps/*war; do if [ $i = pkg-temp/lib/jasper-compiler.jar -o $i = pkg-temp/lib/jbigi.jar ]; then continue; fi; echo pack200 $i; mv $i $i.jar; pack200 -g $i.pack $i.jar; rm -f $i.jar; done" />
         </exec>
         <exec executable="sh" osfamily="mac" failonerror="true">
             <arg value="-c" />
-            <arg value="for i in pkg-temp/lib/*.jar pkg-temp/webapps/*war; do echo pack200 $i; mv $i $i.jar; pack200 -g $i.pack $i.jar; rm -f $i.jar; done" />
+            <arg value="for i in pkg-temp/lib/*.jar pkg-temp/webapps/*war; do if [ $i = pkg-temp/lib/jasper-compiler.jar -o $i = pkg-temp/lib/jbigi.jar ]; then continue; fi; echo pack200 $i; mv $i $i.jar; pack200 -g $i.pack $i.jar; rm -f $i.jar; done" />
         </exec>
         <!-- windoz here : i admit, i hate escaped symbols in xml, indeed = =! -->
         <exec executable="cmd" osfamily="windows" failonerror="true">
             <arg value="/c" />
+            <!-- TODO implement fix above -->
             <arg value="for %i in (pkg-temp\webapps\*.war) do move %i %i.jar &amp;&amp; pack200 -g pkg-temp\webapps\%~ni.war.pack %i.jar &amp;&amp; del %i.jar" />
         </exec>
         <exec executable="cmd" osfamily="windows" failonerror="true">
diff --git a/history.txt b/history.txt
index ca66e959ec..8650baac6d 100644
--- a/history.txt
+++ b/history.txt
@@ -1,3 +1,6 @@
+2012-09-15 zzz
+ * Build: Fix unpack problem on Java 5: http://forum.i2p/viewtopic.php?t=7334
+
 2012-09-14 zzz
  * SSU: Fix shutdown NPE (ticket #709)
 
diff --git a/router/java/src/net/i2p/router/RouterVersion.java b/router/java/src/net/i2p/router/RouterVersion.java
index f7d70ed0aa..3c775e75ad 100644
--- a/router/java/src/net/i2p/router/RouterVersion.java
+++ b/router/java/src/net/i2p/router/RouterVersion.java
@@ -18,7 +18,7 @@ public class RouterVersion {
     /** deprecated */
     public final static String ID = "Monotone";
     public final static String VERSION = CoreVersion.VERSION;
-    public final static long BUILD = 24;
+    public final static long BUILD = 25;
 
     /** for example "-test" */
     public final static String EXTRA = "-rc";