when integrate FCKEditor 2.4.3 with Struts2 + REST plugin,

when I integrate FCKEditor 2.4.3 with Struts2 + REST plugin,the edit box do not appear, in the front , ie shows a script error:
line:54
charachater:2912
error:'$Style' null or is not object
code:0
URL: http://localhost:8080/fckeditor/editor/ ... ar=Default

in the backend:
There is no Action mapped for action name fckeditor. - [unknown location]
at com.opensymphony.xwork2.DefaultActionProxy.prepare(DefaultActionProxy.java:177)
at com.opensymphony.xwork2.DefaultActionProxyFactory.createActionProxy(DefaultActionProxyFactory.java:59)
at org.apache.struts2.rest.RestActionProxyFactory.createActionProxy(RestActionProxyFactory.java:40)
at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:458)
......

Can anybody help me?

Thank you very much.