修复关闭流程实例的时候，刷新待办中心可能报错的问题

o2web/source/x_component_cms_Document/Main.js

@@ -70,8 +70,12 @@ MWF.xApplication.cms.Document.Main = new Class({
     },
     refreshTaskCenter: function(){
         if (this.desktop.apps["cms.Explorer"]){
-            this.desktop.apps["cms.Explorer"].content.unmask();
-            this.desktop.apps["cms.Explorer"].refreshAll();
+            if(this.desktop.apps["cms.Explorer"].content){
+                this.desktop.apps["cms.Explorer"].content.unmask();
+            }
+            if( this.desktop.apps["cms.Explorer"] ){
+                this.desktop.apps["cms.Explorer"].refreshAll();
+            }
         }
     },
     addKeyboardEvents: function(){

o2web/source/x_component_process_Work/Main.js

@@ -80,8 +80,12 @@ MWF.xApplication.process.Work.Main = new Class({
     refreshTaskCenter: function(){
 	    if (this.desktop.apps){
             if (this.desktop.apps["TaskCenter"]){
-                this.desktop.apps["TaskCenter"].content.unmask();
-                this.desktop.apps["TaskCenter"].refreshAll();
+                if(this.desktop.apps["TaskCenter"].content){
+                    this.desktop.apps["TaskCenter"].content.unmask();
+                }
+                if(this.desktop.apps["TaskCenter"].refreshAll){
+                    this.desktop.apps["TaskCenter"].refreshAll();
+                }
             }
         }
     },