Bug 132914 "Invalid page number" error message is hard coded.
"Invalid page number" error message is hard coded in DocumentProcessor.java. This must be externalized into *.properties file. If there are other hard coded error messages, please also externalize.
viewer/org.eclipse.birt.report.viewer/birt/WEB-INF/classes/org/eclipse/birt/report/service/ReportEngineService.java
if ( out == null )
			out = new ByteArrayOutputStream( );
		
		IRenderTask renderTask = null;
		synchronized ( this.getClass( ) )
		{
			renderTask = engine.createRenderTask( reportDocument );
		}
		HashMap context = new HashMap( );
		String format = ParameterAccessor.getFormat( request );
		if ( format.equalsIgnoreCase( ParameterAccessor.PARAM_FORMAT_PDF ) )
		{
			context.put( EngineConstants.APPCONTEXT_PDF_RENDER_CONTEXT,
					createPDFrenderContext( ) );
		}
		else
		{
			context
					.put( EngineConstants.APPCONTEXT_HTML_RENDER_CONTEXT,
							createHTMLrenderContext( svgFlag, request
									.getServletPath( ) ) );
		}
		context.put( EngineConstants.APPCONTEXT_BIRT_VIEWER_HTTPSERVET_REQUEST,
				request );
		context.put( EngineConstants.APPCONTEXT_CLASSLOADER_KEY,
				ReportEngineService.class.getClassLoader( ) );
		renderTask.setAppContext( context );
		
		HTMLRenderOption setting = new HTMLRenderOption( );
		setting.setOutputStream( out );