Maybe like this?
Private Sub runTxShuttleScript(scriptName As String, xlFile As String, sheetName As String, startRow As String, numRows As String, Optional logColumn As String)
    On Error Resume Next

    programm = "c:\program files\winshuttle\txshuttle\txshuttle.exe"
    out = Shell(programm & " " & scriptName & xlFile & sheetName & startRow & numRows & logColumn, vbNormalFocus)
    If Err.Number = 0 Then Exit Sub

    programm = "C:\Program Files\Winshuttle\transactionSHUTTLE8\txshuttle.exe"
    out = Shell(programm & " " & scriptName & xlFile & sheetName & startRow & numRows & logColumn, vbNormalFocus)
    If Err.Number = 0 Then Exit Sub

    programm = "c:\program files\winshuttle\runshuttle8\txrunner.exe"
    out = Shell(programm & " " & scriptName & xlFile & sheetName & startRow & numRows & logColumn, vbNormalFocus)
    If Err.Number = 0 Then Exit Sub

    MsgBox "This operation can only be run on a computer with XXXXX." & vbNewLine & "You do not have the correct software.", _
           vbOKOnly, "No Software Found"
    Sheets("Master").Select
End Sub