I have noticed that when I use the Windows API, I cannot play some avi files. the following is the code I use, and it only works for some avi files. Why????

In general, declarations area:
Private Declare Function mciSendString Lib "winmm.dll" Alias _
"mciSendStringA" (ByVal lpstrCommand As String, ByVal _
lpstrReturnString As Any, ByVal uReturnLength As Long, ByVal _
hwndCallback As Long) As Long
Public FileName
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Open App.Path & "\" & App.EXEName & ".stp" for Input As #1
Input #1, FileName
close #1

Last$ = ScreenSaver.hWnd & " Style " & &H40000000
ToDo$ = "open " & FileName & " Type avivideo alias video parent " & Last$
i = mciSendString(ToDo$, 0&, 0, 0)
i = mciSendString("play video repeat", 0&, 0, 0)