FullCalendar on JQueryWidgetBox not work

I use Seaside 3.1, Pharo 3.0,  on Ubuntu 14.04.

I need to use fullcalendar on JQWidgetBox but does not work.

When I try to access it with url:     <a rel="nofollow" target="_blank" onclick="return theMainWindow.showLinkWarning(this)" href="http://localhost:9090/jquery-widgets/fullcalendar" id="yiv8956222144yui_3_16_0_1_1421198721822_17023">http://localhost:9090/jquery-widgets/fullcalendar

Error message is:

MessageNotUnderstood:  receiver of "encodeCollection:on:" is nil

Thanks for the support

Oswall