Groovy apparently needs ant version 1.7 to build, or at least ant 1.6.5 rather than ant 1.6.2, so it might be worth adding an explicit version check to the ant build file to prevent the build failing half-way through... <target name="checkVersion" description="Ensure that we're running ant 1.7"> <fail message="Please install using ant 1.7"> <condition> <not> <contains string="${ant.version}" substring="1.7"/> </not> </condition> </fail> </target>