MultiFileUpload add-on issue

I am trying to use the “wcslib-vaadin-widget-multifileupload” (v 1.9) add on. When i try to use the multiple file upload it’s throwing this error. Single file upload works. Any idea why i am getting this error?

Widgetset ‘com.vaadin.DefaultWidgetSet’ does not contain implementation for com.wcs.wcslib.vaadin.widget.multifileupload.component.MultiUpload. Check its component connector’s @Connect mapping, widgetsets GWT module description file and re-compile your widgetset.

I am using vaddin 7.5.3.

Thanks

Have you solve the problem?