First, did you download this package?: http://sourceforge.net/projects/ant-contrib/files/ant-contrib/1.0b3/ant-contrib-1.0b3-bin.zip/download
The ones on the top are only for the cpp tasks. I don't know why it's not obvious which one you're suppose to download. You're suppose to have a file called "ant-contrib-1.0b3.jar". You need to put this JAR in the "lib" directory under where you have Ant installed. If you've done that, you need this line: <taskdef resource="net/sf/antcontrib/antcontrib.properties"/> You don't need the "libpath" parameter because the ant-contrib JAR is in the lib folder of your Ant installation. If you can't install the jarfile in your Ant's lib folder, then install it in a folder called "lib" under the directory where your build.xml is located. Then try this: <classpath id="contrib.classpath.ref"> <fileset dir="${basedir}/lib"/> </classpath> <taskdef resource="net/sf/antcontrib/antcontrib.properties" classpathref="contrib.classpath.ref"/> That will allow Ant to find the ant-contrib JAR file. -- David Weintraub qazw...@gmail.com