title: class EVariantTypeCastError with message 'Could not convert variant of type (String) into type (Double)
body: <p>Using Delphi and FastReport I get this error message while debugging inside Delphi immediately after this line:</p>
  
  <pre><code>&lt;FastReport_Component&gt;.ShowReport(true);
  </code></pre>
  
  <p>Then this error appear:</p>
  
  <blockquote>
    <p>Project myapp.exe raised exception class EVariantTypeCastError with message 'Could not convert variant of type
    (String) into type (Double)'.</p>
  </blockquote>
  
  <p>It appears twice before displaying the report. but if I run myapp without debugging no error message appear.</p>
  
  <p>How I can find which memo cause this error ? the report has so many memos. some has also expressions inside using <code>IIF</code> and the error message does not display any more info. </p>