Trouble With Ant Runner

I installed 4.5 and setup a project which uses the Ant runner.  After staring the agent (this is running under linux) I found that the agent doesnt support the Ant Runner.  I looked and saw that in the plugins directory was antPlugin.zip and ant.jar.  I unzipped the antPlugin.zip.

Now, when I start the agent, it sees the ant plugin but fails to load it with:

[2009-10-27 09:47:34,428]  ERROR - gins.spring.SpringPluginLoader - Failed to initialize spring context for plugin coveragePlugin
java.lang.NoClassDefFoundError: org/apache/tools/ant/BuildEvent
        at java.lang.Class.getDeclaredMethods0(Native Method)
        at java.lang.Class.privateGetDeclaredMethods(Class.java:2427)
        at java.lang.Class.getDeclaredMethods(Class.java:1791)
        at org.springframework.util.ReflectionUtils.doWithMethods(ReflectionUtils.java:396)
        at org.springframework.util.ReflectionUtils.doWithMethods(ReflectionUtils.java:379)
        .......


Any ideas what is going on?