Grails Clover plugin wont install on Windows

      [get] last modified = Wed Feb 24 23:48:32 EST 2010
Reading remote plugin list ...
      [get] Getting: http://plugins.grails.org/.plugin-meta/plugins-list.xml
      [get] To: C:\Documents and Settings\Giles Gaskell\.grails\1.2.1\plugins-li
st-default.xml
................................
      [get] last modified = Thu Mar 04 05:21:29 EST 2010
      [get] Getting: https://svn.codehaus.org/grails-plugins/grails-clover/tags/
RELEASE_0_2/grails-clover-0.2.zip
      [get] To: C:\Documents and Settings\Giles Gaskell\.grails\1.2.1\plugins\gr
ails-clover-0.2.zip
      [get] Error getting https://svn.codehaus.org/grails-plugins/grails-clover/
tags/RELEASE_0_2/grails-clover-0.2.zip to C:\Documents and Settings\Giles Gaskel
l\.grails\1.2.1\plugins\grails-clover-0.2.zip
: javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException
: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderEx
ception: unable to find valid certification path to requested target
        at org.apache.tools.ant.taskdefs.Get.execute(Get.java:82)
        at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.jav
a:106)
        at org.apache.tools.ant.Task.perform(Task.java:348)
        at InstallPlugin$_run_closure34.doCall(InstallPlugin:1422)
        at InstallPlugin$_run_closure34.call(InstallPlugin)
        at InstallPlugin$_run_closure26_closure82.doCall(InstallPlugin:983)
        at InstallPlugin$_run_closure26_closure82.doCall(InstallPlugin)
        at InstallPlugin$_run_closure26.doCall(InstallPlugin:956)
        at InstallPlugin$_run_closure26.call(InstallPlugin)
        at InstallPlugin$_run_closure32_closure88.doCall(InstallPlugin:1214)
        at InstallPlugin$_run_closure32_closure88.doCall(InstallPlugin)
        at InstallPlugin.withPluginInstall(InstallPlugin:1253)
        at InstallPlugin.this$4$withPluginInstall(InstallPlugin)
        at InstallPlugin$_run_closure32.doCall(InstallPlugin:1213)
        at InstallPlugin$_run_closure32.call(InstallPlugin)
        at InstallPlugin$_run_closure2.doCall(InstallPlugin:73)
        at gant.Gant$_dispatch_closure4.doCall(Gant.groovy:324)
        at gant.Gant$_dispatch_closure6.doCall(Gant.groovy:334)
        at gant.Gant$_dispatch_closure6.doCall(Gant.groovy)
        at gant.Gant.withBuildListeners(Gant.groovy:344)
        at gant.Gant.this$2$withBuildListeners(Gant.groovy)
        at gant.Gant$this$2$withBuildListeners.callCurrent(Unknown Source)
        at gant.Gant.dispatch(Gant.groovy:334)
        at gant.Gant.this$2$dispatch(Gant.groovy)
        at gant.Gant.invokeMethod(Gant.groovy)
        at gant.Gant.processTargets(Gant.groovy:495)
        at gant.Gant.processTargets(Gant.groovy:480)