Proguard Error with ant/antenna

[earamsey]

I get the following proguard error:
[wtkobfuscate] java.io.IOException: The output jar is empty. Did you specify the proper '-keep' optons?
Any idea what is wrong?
Thanks,
earamsey

------- actual ant output: ------------
[wtkobfuscate] Obfuscating C:\Projects\J2ME\CellStory\bin\CellStory.jar with ProGuard
[wtkobfuscate] ProGuard, version 3.2
[wtkobfuscate] Reading jars...
[wtkobfuscate] Reading program jar [C:\Projects\J2ME\CellStory\bin\CellStory.jar]
[wtkobfuscate] Reading library zip [C:\WTK22\wtklib\devices\Series_60_MIDP_SDK_2_1\lib\kmidp20.zip]
[wtkobfuscate] Removing unused library classes...
[wtkobfuscate] Original number of library classes: 305
[wtkobfuscate] Final number of library classes: 6
[wtkobfuscate] Shrinking...
[wtkobfuscate] Removing unused program classes and class elements...
[wtkobfuscate] Original number of program classes: 1
[wtkobfuscate] Final number of program classes: 0
[wtkobfuscate] java.io.IOException: The output jar is empty. Did you specify the proper '-keep' options?
^^^^^___Error that I get is here
[wtkobfuscate] at proguard.ProGuard.shrink(ProGuard.java:474)
[wtkobfuscate] at proguard.ProGuard.execute(ProGuard.java:86)
[wtkobfuscate] at proguard.ProGuard.main(ProGuard.java:916)

Here is my build.xml file:

<?xml version="1.0" encoding="UTF-8"?>
<project name="MIDP2.0" default="n66xx" basedir=".">
    <description>
	Build file for MyLittleProject
    </description>
    <!-- predefined antenna tasks -->
    <taskdef resource="antenna.properties"/>
    <!-- ProGuard home -->
    <property name="wtk.proguard.home" value="C:\proguard3.2"/>
    <!-- RetroGuard home -->
    <property name="wtk.retroguard.home" value="C:\retroguard-v2.0.2"/>
    <property name="midlet.name" value="MyLittleProject"/>
    <property name="midlet.home" value="C:\Projects\J2ME\MyLittleProject"/>
    <target name="build" description="Builds everything">
	<antcall target="n66xx"/>
    </target>
    <target name="n66xx" description="Builds Nokia Models 6600 and 6620">
	<ant dir="devices/nokia66xx" inheritall="true" target="build"/>
    </target>
    <target name="cellstory_init" description="Create directory structure">
	<property name="src_pp" location="${preproc_dir}"/>
	<!-- set global properties -->
	<property name="src" location="src"/>
	<property name="bin" location="bin"/>
	<property name="res" location="res"/>
	<property name="classes" location="classes"/>
	<!-- Create the timestamp -->
	<tstamp/>
	<!-- Make directories -->
	<mkdir dir="${src}"/>
	<mkdir dir="${src_pp}"/>
	<mkdir dir="${bin}"/>
	<mkdir dir="${res}"/>
	<mkdir dir="${classes}"/>
    </target>
    <target name="cellstory" depends="cellstory_init" description="Build it all">
	<wtkjad
	    jadfile="${bin}/${midlet.name}.jad"
	    jarfile="${midlet.name}.jar"
	    name="MyLittleProject"
	    vendor="Wizzards and Lizzards"
	    version="1.0.0">
	    <midlet
		name="${midlet.name}"
		icon="${midlet.name}.png"
		class="${midlet.name}.class"/>
	    <attribute
		name="deleteConfirm"
		value="Do you really want to delete me?"/>
	</wtkjad>
	<!-- do preprocessing -->
	<wtkpreprocess
	    srcdir="${src}"
	    destdir="${src_pp}"
	    symbols="${symbols}"/>
	<!-- Compile the code -->
	<wtkbuild
	    srcdir="${src_pp}"
	    destdir="${classes}"
	    deprecation="on"
	    target="1.4"
	    source="1.4"/>
	<!-- Package the classes -->
	<wtkpackage 
	    jarfile="${bin}/${midlet.name}.jar"
	    jadfile="${bin}/${midlet.name}.jad"
	    obfuscate="false"
	    preverify="false">
	    <fileset dir="${classes}" includes="**/*.class"/>
	    <fileset dir="${res}" includes="**"/>
	</wtkpackage>
	<wtkobfuscate
	    jarfile="${bin}/${midlet.name}.jar"
	    jadfile="${bin}/${midlet.name}.jad"
	    tojarfile="${bin}/${midlet.name}._jar"
	    obfuscator="proguard">
	</wtkobfuscate>
	<wtkpreverify jarfile="${bin}/${midlet.name}.jar"/>
	<!-- run -->
	<wtkrun jadfile="${bin}/${midlet.name}.jad" device="Series_60_MIDP_SDK_2_1"/>
    </target>
    <target name="cleanbuild" description="Cleans and builds">
	<ant dir="devices/nokia66xx" inheritall="true" target="cleanbuild"/>
    </target>
</project>