Delete fails...

[dcorbin]

I've the following ANT script:

<project name="Junit install" default="install" basedir=".">
        <property name="archive" value="junit3.5"/>
        <property name="archivetype" value="zip"/>

        <target name="prepare">
                <available file="is.installed" property="is.installed" />
        </target>

        <target name="install" depends="prepare" unless="is.installed">
                <unzip src="${archive}.${archivetype}" dest="."/>
                <touch file="is.installed" />
        </target>

        <target name="clean">
                <delete dir="${archive}"/>
                <delete file="is.installed"/>
        </target>
</project>


I'm getting the following result: 

Buildfile: build.xml

clean:
   [delete] Deleting directory C:\data\Source\CMS\ThirdParty\junit\junit3.5

BUILD FAILED

C:\data\Source\CMS\ThirdParty\junit\build.xml:15: Unable to delete file 
C:\data\Source\CMS\ThirdParty\junit\junit3.5\junit.jar


ATTRIB shows that the file is not readonly:
C:\data\Source\CMS\ThirdParty\junit>attrib junit3.5\*
           C:\data\Source\CMS\ThirdParty\junit\junit3.5\junit.jar
A          C:\data\Source\CMS\ThirdParty\junit\junit3.5\README.html
A          C:\data\Source\CMS\ThirdParty\junit\junit3.5\src.jar

This seems to work fine on Linux, and fail on Windows 2000.  Any ideas?