vb 实时错误53

这是我的一段代码，主要用来将AVI文件转换为MPG文件，但是运行时，我能够生成AVI文件，但是一但点击生成MPG文件，就会出现“ 实时错误53”。这是转MPG文件的代码
'生成MPG
Private Sub Command12_Click()
  Dim Mpgest, Mpger, TheMovie As String
  SetTopMostWindow Me.hWnd, False
  'm2apx3g.exe -b PoppingAssCherry1-7.mpg -f -o7 output.avi
  'avi2mpg1 [-options] inputfile.avi [outputfile.mpg]
  Dim RetVal
  TheMovie = App.Path & "\MyAVI.avi"
  Mpger = App.Path & "\MyMPEG1.mpg"
  'Mpgest = App.Path & "\m2apx3g.exe -b " & TheMovie & " -f -o7 " & Mpger & ".avi"
  Mpgest = App.Path & "\avi2mpg1.exe -n -f1 " & TheMovie & " " & Mpger
  RetVal = Shell(Mpgest, 1) '这里出现“文件未找到”的错误

End Sub

Private Sub Command13_Click() '播放MPG
SeeFlag = "mpg"
Load Form1
Form1.Show
End Sub

Private Sub Command2_Click() '生成AVI文件
Dim i As Long
Load fMain
fMain.Show
File1.Refresh
For i = 0 To File1.ListCount - 1
  fMain.lstDIBList.AddItem App.Path & "\Images\" & File1.List(i)
Next
fMain.cmdWriteAVI_Click
Unload fMain
Set fMain = Nothing
End Sub

Private Sub Command2_MouseDown(Button As Int