error in use dchart

when use dchart , show this error !
don’t use gwt and don’t have .gwt.xml file
don’t have pom.xml file
i use intellij IDE

Widgetset ‘com.vaadin.DefaultWidgetSet’ does not contain implementation for org.dussan.vaadin.dcharts.DCharts. Check its component connector’s @Connect mapping, widgetsets GWT module description file and re-compile your widgetset. In case you have downloaded a vaadin add-on package, you might want to refer to add-on instructions.

have any idea?