java.lang.NoClassDefFoundError

ant
Buildfile: build.xml
BUILD FAILED
java.lang.NoClassDefFoundError: org/apache/tools/ant/util/DeweyDecimal
        at com.android.ant.SetupTask.getVersion(SetupTask.java:600)
        at com.android.ant.SetupTask.execute(SetupTask.java:83)
        at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:275)
        at org.apache.tools.ant.Task.perform(Task.java:364)
        at org.apache.tools.ant.Target.execute(Target.java:341)
        at org.apache.tools.ant.helper.ProjectHelper2.parse(ProjectHelper2.java:142)
        at org.apache.tools.ant.ProjectHelper.configureProject(ProjectHelper.java:91)
        at org.apache.tools.ant.Main.runBuild(Main.java:653)
        at org.apache.tools.ant.Main.startAnt(Main.java:187)
        at org.apache.tools.ant.launch.Launcher.run(Launcher.java:246)
        at org.apache.tools.ant.launch.Launcher.main(Launcher.java:67)
Caused by: java.lang.ClassNotFoundException: org.apache.tools.ant.util.DeweyDecimal
        at org.apache.tools.ant.AntClassLoader.findClassInComponents(AntClassLoader.java:1166)
        at org.apache.tools.ant.AntClassLoader.findClass(AntClassLoader.java:1107)
        at org.apache.tools.ant.AntClassLoader.loadClass(AntClassLoader.java:977)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:266)
        ... 11 more
Total time: 0 seconds