[Subclipse-users] Url@revision syntax not working

Hi,
I have the following basic build file.
<?xml version="1.0" encoding="UTF-8"?>
<project default="myTarget">
<taskdef name="svn" classname="org.tigris.subversion.svnant.SvnTask
"></taskdef>
<target name="myTarget">
     <svn>
    <checkout url="svn://10.0.52.139:3690" destPath="C:/ant_svn_test"/>
    </svn>
</target>
</project>

When i try and build this file i get the following result
--start result--
Buildfile: build.xml

myTarget:
      [svn] Using command line interface
Svn : Checking out a working copy from a repository :
co -r HEAD svn://10.0.52.139@HEAD C:\ant_svn_test --non-interactive
svn: Unknown hostname 'HEAD'

BUILD FAILED
C:\Documents and Settings\puneet\My Documents\ant
experimentation\build.xml:6:
Can't checkout

Total time: 13 seconds
--end result----

I tried executing the same command directly from the command line instead of
through the svnant task and i still get the same error. But when i try
something like the following(without the @HEAD syntax)

svn co -r HEAD svn://10.0.52.139 from the command line it works properly.

I believe the problem is the url@revision syntax which somehow my shell is
not able to recognize. I am using Windows XP.

I would appreciate any help on the issue.

Thanks

-- 
Puneet