Help:使用tapestry的contrib:Table时，其source的值的问题？

.java文件中：
public void pageBeginRender(PageEvent event) {
  if (getUser()==null) {
   getRequestCycle().activate("Home");
  }
  // if (!getRequestCycle().isRewinding()){    ！！如果这行不注释掉，就会出现这个错误，注释掉这行就可以正常运行，是为什么啊？
   List<KhItem> itemList=getKhImpl().getKhTodo(getUser().getUserID());
   for(int i=0;i<itemList.size();i++)
    itemList.get(i).setOrderNum(i+1);
    setTodoList(itemList);
  //}
 }

在.page文件中；
<property name="todoList" />
<component id="toDoTable" type="contrib:Table">
  <binding name="source" value="todoList"/>
  <binding name="columns" value="literal:orderNum,khCategaryName,khBegintime,khEndtime,employeeName,todo"/>
  <binding name="pageSize" value="30"/>
  <binding name="tableSessionStateManager"
   value="new org.apache.tapestry.contrib.table.model.common.FullTableSessionStateManager()"/>
 </component>

在.html文件中：
<table class="ForrestTable" cellspacing="1" cellpadding="4" jwcid="toDoTable">
   <tr><th></th><th></th><th></th><th></th><th></th><th></th></tr>
   <tr >
   <td></td>
   <td></td>
   <td></td>
   <td></td>
   <td></td>
   <td jwcid="todoColumnValue@Block" >
    <input jwcid="@Submit" listener="listener:khDetail" parameters="ognl:components.toDoTable.tableRow" value="去评 "/>
   </td>
   </tr>
   </table>

错误：

org.apache.hivemind.ApplicationRuntimeException

Either the tableModel parameter or both source and columns parameters must be specified by component Role/toDoTable.tableView

Stack Trace:

org.apache.tapestry.contrib.table.components.TableView.getTableModel(TableView.java:220) org.apache.tapestry.contrib.table.components.TableView.validateValues(TableView.java:465) org.apache.tapestry.contrib.table.components.TableView.renderComponent(TableView.java:497) $TableView_86.renderComponent($TableView_86.java) org.apache.tapestry.AbstractComponent.render(AbstractComponent.java:617) org.apache.tapestry.BaseComponent.renderComponent(BaseComponent.java:92) org.apache.tapestry.AbstractComponent.render(AbstractComponent.java:617) org.apache.tapestry.AbstractComponent.renderBody(AbstractComponent.java:434) org.apache.tapestry.components.IfBean.renderComponent(IfBean.java:86) $IfBean_71.renderComponent($IfBean_71.java) org.apache.tapestry.AbstractComponent.render(AbstractComponent.java:617) org.apache.tapestry.AbstractComponent.renderBody(AbstractComponent.java:434) org.apache.tapestry.form.FormSupportImpl.rewind(FormSupportImpl.java:573) org.apache.tapestry.form.Form.renderComponent(Form.java:226)