code: protected void error(String msg, Exception e)
            throws org.xml.sax.SAXException
    {
  
      SAXSourceLocator locator = getLocator();
      ErrorListener handler = m_stylesheetProcessor.getErrorListener();
      TransformerException pe;
  
      if (!(e instanceof TransformerException))
      {
        pe = (null == e)
             ? new TransformerException(msg, locator)
             : new TransformerException(msg, locator, e);
      }
      else
        pe = (TransformerException) e;
  
      if (null != handler)
      {
        try
        {
          handler.error(pe);
        }
        catch (TransformerException te)
        {
          throw new org.xml.sax.SAXException(te);
        }
      }
      else
        throw new org.xml.sax.SAXException(pe);
    }
docs: Tell the user of an error, and probably throw an
  exception.
  
  @param msg An error message.
  @param e An error which the SAXException should wrap.
  
  @throws org.xml.sax.SAXException that wraps a
  {@link javax.xml.transform.TransformerException} if the current
  {@link javax.xml.transform.ErrorListener#error}
  method chooses to flag this condition as an error.
  @xsl.usage internal