code: public String getErrorMessage() {
  
          StringBuffer result = new StringBuffer(512);
  
          String reason = m_messages.key(Messages.GUI_REASON_0, new Object[] {});
  
          if (CmsStringUtil.isNotEmpty(m_errorMessage)) {
              result.append(m_errorMessage);
              result.append("\n").append(reason).append(": ");
          }
  
          // if a localized message is already set as a parameter, append it.
          result.append(getMessage(m_throwable));
          // recursively append all error reasons to the message
          for (Throwable cause = m_throwable.getCause(); cause != null; cause = cause.getCause()) {
              result.append("\n").append(reason).append(": ");
              result.append(getMessage(cause));
          }
          return result.toString();
      }
docs: Returns the error message to be displayed.<p>
  
  @return the error message to be displayed