用EXCEL来控制CST 运行，出错了，怎么回事？

参照example里提供的demo例子，自己试着写了一个：模型结构已经在CST里建好，主要是想修改激励源，来控制CST仿真。VBA语言如下：
Option Explicit
Sub mwsconnect()
' Next open a connection to CST DESIGN ENVIRONMENT
Dim studio As Object
Set studio = CreateObject("CSTStudio.Application")
' Now open the model file which is located in the same folder as the Excel sheet
' This will also return a connection to CST MICROWAVE STUDIO
Dim path As String
Dim fname As String
path = ActiveWorkbook.path
Dim mws As Object
Set mws = studio.OpenFile(path & "\lojiedigis1MHz_sinExcition.cst")
mws.DeleteResults
With mws.TimeSignal
     .Reset
     .Name "default"
     .SignalType "Sine step"
     .ProblemType "High Frequency"
     .Ttotal "2"
     .Phase "0.0"
     .Frequency "1"
     .RiseFactor "0.0001"
     .Create
End With
mws.Rebuild
' Make a connection to the solver and start the simulation
mws.solver.Start
mws.Save
' Finally close the connection to CST MICROWAVE STUDIO
studio.Quit
Set studio = Nothing
End Sub
但是EXCEL 提示未找到文件！现在CST提供的demo例子也不知道被我改了什么也提示这个错误。上面的VBA有错吗?还有那个EXCEL提示未找到文件是原因啊?谢谢！
还有在按EXCEL里的VBA保存时，经常提示如下错误。这是为什么啊?谢谢！