clearantlib

I have a simple build.xml file, but I can not make it worked with clearantlib. Please help.
Thanks,
Ha
Below is the listing of build.xml and error encounterred:
------
build.xml listing:

<project name="ccant" basedir="." default="cc-tasks" xmlns:ca="antlib:net.sourceforge.clearantlib">

<target name="cc-tasks">
<!-- remove the label type--> <ca:ccexec failonerror="true"> <arg value="describe"/> <arg line="-short"/> <arg value="C:\ccweb_ha15747\ha15747_ProjetHL7\CVOB_DSEI\HL7IntegrationDriver\CommonPlatform"/> </ca:ccexec>

</target>
</project>

------
error encounterred:

C:\ccweb_ha15747\ha15747_ProjetHL7\CVOB_DSEI>ant
Buildfile: build.xml

cc-tasks:

BUILD FAILED
java.lang.UnsupportedClassVersionError: net/sourceforge/clearantlib/ClearToolApp
ly (Unsupported major.minor version 49.0)
at java.lang.ClassLoader.defineClass0(Native Method)
at java.lang.ClassLoader.defineClass(Unknown Source)
at java.security.SecureClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.access$100(Unknown Source)
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at org.apache.tools.ant.AntClassLoader.findBaseClass(AntClassLoader.java
:1425)
at org.apache.tools.ant.AntClassLoader.loadClass(AntClassLoader.java:108
4)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClassInternal(Unknown Source)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Unknown Source)
at org.apache.tools.ant.taskdefs.Definer.addDefinition(Definer.java:583)

at org.apache.tools.ant.taskdefs.Definer.execute(Definer.java:228)
at org.apache.tools.ant.taskdefs.Antlib.execute(Antlib.java:161)
at org.apache.tools.ant.taskdefs.Definer.loadAntlib(Definer.java:432)
at org.apache.tools.ant.taskdefs.Definer.execute(Definer.java:281)
at org.apache.tools.ant.ComponentHelper.checkNamespace(ComponentHelper.j
ava:790)
at org.apache.tools.ant.ComponentHelper.getDefinition(ComponentHelper.ja
va:260)
at org.apache.tools.ant.ComponentHelper.createComponent(ComponentHelper.
java:237)
at org.apache.tools.ant.ComponentHelper.createComponent(ComponentHelper.
java:216)
at org.apache.tools.ant.UnknownElement.makeObject(UnknownElement.java:41
4)
at org.apache.tools.ant.UnknownElement.maybeConfigure(UnknownElement.jav
a:160)
at org.apache.tools.ant.Task.perform(Task.java:347)
at org.apache.tools.ant.Target.execute(Target.java:357)
at org.apache.tools.ant.Target.performTasks(Target.java:385)
at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1337)
at org.apache.tools.ant.Project.executeTarget(Project.java:1306)
at org.apache.tools.ant.helper.DefaultExecutor.executeTargets(DefaultExe
cutor.java:41)
at org.apache.tools.ant.Project.executeTargets(Project.java:1189)
at org.apache.tools.ant.Main.runBuild(Main.java:758)
at org.apache.tools.ant.Main.startAnt(Main.java:217)
at org.apache.tools.ant.launch.Launcher.run(Launcher.java:257)
at org.apache.tools.ant.launch.Launcher.main(Launcher.java:104)

Total time: 0 seconds