Bug 147407 Preview the attached report in the web viewer first time and then click the TOC button will cause NPE error
Description: It just can be reprouduced at first time preview. Step to reproduce: 1. please use attach report file 2. preview it in the web viewer 3. click the "Toggle table of contents" button Actual result: As the atteched screenshot shows,There is a NPE error.And if you preview it in the Web viewer again, the phenomenon is disappear.But reopen the eclipse and preview it at first time, it will be occured.
viewer/org.eclipse.birt.report.viewer/birt/WEB-INF/classes/org/eclipse/birt/report/utility/ParameterAccessor.java
? getReportParameter( request, PARAM_BOOKMARK, null )
				: null;
	}
	/**
	 * Get query string with new parameter value.
	 * 
	 * @param request
	 *            http request
	 * @param name
	 *            parameter name
	 * @param value
	 *            default parameter value
	 * @return new query string with new parameter value
	 */
	public static String getEncodedQueryString( HttpServletRequest request,
			String name, String value )
	{
		String queryString = ""; 
		Enumeration e = request.getParameterNames( );
		Set nullParams = getParameterValues( request, PARAM_ISNULL );
		boolean isFirst = true;
		while ( e.hasMoreElements( ) )
		{
			String paramName = (String) e.nextElement( );
			if ( paramName != null
					&& !paramName.equalsIgnoreCase( PARAM_ISNULL ) )
			{
				String paramValue = getParameter( request, paramName, false );
				if ( nullParams != null
						&& nullParams.remove( toUTFString( paramName ) )