FCKEditor and YUICompressor

I am trying to minify all javascript (including FCKEditor) during the ANT build using YUICompressor, but I am getting errors from FCKEditor.

At the moment I cannot tell which file is causing the error because ANT is not echoing the file name.

The task I am using is defined as follows.
<target name="js.minify" depends="init">
<description>minify js files</description>
<apply executable="java" parallel="false" failonerror="true" verbose="true" >
<arg value="-jar"/>
<arg file="${tools.dir}/${yuicompressor}"/>
<arg value="--charset"/>
<arg value="ISO-8859-1"/>
<arg value="--nomunge"/>
<arg value="--preserve-semi"/>
<arg value="-o"/>
<targetfile/>
<srcfile/>

<!-- files are processed in alpha-order so that we can know the progress,
and easily identify the file that is failed.-->
<sort xmlns:rcmp="antlib:org.apache.tools.ant.types.resources.comparators">
<rcmp:name/>
<fileset dir="C:\fckeditor">
<include name="**/*.js"/>
<!-- avoid cycling -->
<exclude name="**/*-min.js"/>
</fileset>
</sort>
<!-- define output file name -->
<mapper type="glob" from="*.js" to="*-min.js"/>
</apply>
</target>

Is there any reason this shouldn't work on FCKEditor?