title: iReport: Error when compiling report with subreport
body: <p>The following .jrxml:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="UTF-8"?&gt;
  &lt;jasperReport xmlns="http://jasperreports.sourceforge.net/jasperreports" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://jasperreports.sourceforge.net/jasperreports http://jasperreports.sourceforge.net/xsd/jasperreport.xsd" name="DTC-Campaigns-Block-Campaigns-Helper-Campaigns" language="groovy" pageWidth="794" pageHeight="450" orientation="Landscape" columnWidth="794" leftMargin="0" rightMargin="0" topMargin="0" bottomMargin="0"&gt;
      &lt;queryString&gt;&lt;![CDATA[SELECT 1;]]&gt;&lt;/queryString&gt;
      &lt;detail&gt;
          &lt;band height="50" splitType="Stretch"&gt;
              &lt;subreport&gt;
                  &lt;reportElement x="0" y="0" width="794" height="25"/&gt;
                  &lt;subreportExpression class="java.lang.String"&gt;&lt;![CDATA["./test.jasper"]]&gt;&lt;/subreportExpression&gt;
              &lt;/subreport&gt;
          &lt;/band&gt;
      &lt;/detail&gt;
  &lt;/jasperReport&gt;
  </code></pre>
  
  <p>won't compile within iReport 3.6.0:</p>
  
  <pre><code>Compiling to file... /home/dominik/workspace/project1/reporting/MyFile.jasper
  Compiling subreports....
  Unable to locate the subreport with expression: "$P{SUBREPORT_DIR} + "test.jasper"".
  </code></pre>
  
  <p>Even fixing <code>SUBREPORT_DIR</code> to <code>./</code> won't help, neither will compiling <code>test.jrxml</code> manually before the master report.</p>
  
  <p>Any ideas?</p>