插件无法启动

各位高手们：

我按着书上的例子建立VB DLL插件，做了引用(SW2007)三个必须的引用，写了下面语句

编译DLL也成功了，但是在SW中打开DLL时提示 :插件无法启动，是怎么回事啊？？？

拿光盘附带的例子DLL也同样有这样的问题，我用的是SW2007，是不是版本不对？

Implements SWPublished.SwAddin
Dim swApp As SldWorks.SldWorks
Dim swModel As SldWorks.ModelDoc2
Dim swCookie As Long
Dim swToolbarID As Long

Private Function SwAddin_ConnectToSW(ByVal ThisSW As Object, ByVal Cookie As Long) As Boolean
Set swApp = ThisSW
swCookie = Cookie
swApp.SetAddinCallbackInfo App.hInstance, Me, swCookie
swApp.AddMenu swDocPART, "形状", 5
swApp.AddMenuItem2 swDocPART, swCookie, "立方体@形状", -1, "Block_MenuCallback", "", ""
End Function

Private Function SwAddin_DisconnectFromSW() As Boolean
swApp.RemoveMenu swDocPART, "形状", ""
End Function

谢谢