Bug 134229 [smoke][regression] fail to export data as csv format
steps to reproduce: - use the attached report - preview in web viewer - export data - select data - click on OK expected behavior: - data is exported (as csv format) actual behavior: - nothing happened
viewer/org.eclipse.birt.report.viewer/birt/WEB-INF/classes/org/eclipse/birt/report/servlet/ViewerServlet.java
private IFragment engine = null;
	private IFragment parameter = null;
	/**
	 * Servlet path for parameter model.
	 */
	public static final String SERVLET_PATH_PARAMETER = "/parameter"; 
	/**
	 * Servlet path for preview model.
	 */
	public static final String SERVLET_PATH_PREVIEW = "/preview"; 
	/**
	 * Servlet path for frameset model.
	 */
	public static final String SERVLET_PATH_FRAMESET = "/frameset"; 
	/**
	 * Servlet path for running model.
	 */
	public static final String SERVLET_PATH_RUN = "/run"; 
	/**
	 * The error page.
	 */
	private static final String EORROR_PAGE = "pages/common/Error.jsp";
	/**
	 * Servlet initialization. Initialize engine, parameter, resources, and
	 * viewer fragment. Birt viewer uses a composite of fragments to control the
	 * layout renderring. The Composite is initialized here and will be shared
	 * by all incoming servlet requests. Four fragment references are stored as
	 * properties of servlet instance. Each fragments is read only.
	 * 
	 * @see org.eclipse.birt.report.viewer.aggregation.BaseFragment