When testing the junitreport task from fresh ant build from svn, I do not get 
an html report when selecting the format noframes.
When the frames format is used, the task works. Then it creates the html files.

This still worked for a svn checkout of approx. 10 days ago.
It first failed in the checkout I did yesterday june 10.

My taskdef looks like this:
    <junitreport >
      <fileset dir="${test.result.dir}">
        <include name="TEST-*.xml"/>
      </fileset>
      <report format="noframes" todir="."/>
    </junitreport>


The ant log displays no errors:
[junitreport] Loading stylesheet jar:file:/C:/sandbox_ant/ant/ant-
trunk/dist/lib
/ant-junit.jar!/org/apache/tools/ant/taskdefs/optional/junit/xsl/junit-
noframes.
xsl
[junitreport] Transform time: 687ms
[junitreport] Deleting: C:\DOCUME~1\JANCUM~1\LOCALS~1\Temp\null1771508224

But it doesn't seem to generate the report.