Hvordan åbner man en fil med et bestemt program via VB

'I Modul
Declare Function ShellExecute Lib "shell32.dll" Alias "ShellExecuteA" (ByVal hwnd As Long, ByVal lpOperation As String, ByVal lpFile As String, ByVal lpParameters As String, ByVal lpDirectory As String, ByVal nShowCmd As Long) As Long

'Kaldet:
a = ShellExecute(hwnd, "Open", Sti+filnavn, Sti+filnavn, "", 1)

Dette er koden jeg har stående i min Form:

Public Class Form1
    Declare Function ShellExecute Lib "shell32.dll" Alias "ShellExecuteA" (ByVal hwnd As Long, ByVal lpOperation As String, ByVal lpFile As String, ByVal lpParameters As String, ByVal lpDirectory As String, ByVal nShowCmd As Long) As Long


    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        a = ShellExecute(hwnd, "Open", C:\Programmer\VideoLAN\VLC\vlc.exe , C:\cd1.wma, "", 1)
    End Sub

End Class

Den finder en række errors i koden, ved ikke om jeg har misforstået noget.