Set wdApp = CreateObject("Word.Application")

Dim strFileToOpen As String
strFileToOpen = Application.GetOpenFilename
If strFileToOpen = False Then
MsgBox "No file selected.", vbExclamation, "Sorry!"
Exit Sub
Else
Workbooks.Open Filename:=strFileToOpen
End If

Private Sub CommandButton1_Click()
....
Dim wdApp As Object
Dim wdDock As Object
Set wdApp = CreateObject("Word.Application")
Set wdDock = wdApp.Documents.Open(GetFilePath("Выберите файл Word", , "Документы Word", "*.doc"))
....
End Sub

Function GetFilePath(Optional ByVal Title As String = "Выберите файл для обработки", _
                     Optional ByVal InitialPath As String = "c:\", _
                     Optional ByVal FilterDescription As String = "Книги Excel", _
                     Optional ByVal FilterExtention As String = "*.xls*") As String
    On Error Resume Next
    With Application.FileDialog(msoFileDialogOpen)
        .ButtonName = "Выбрать": .Title = Title: .InitialFileName = InitialPath
        .Filters.Clear: .Filters.Add FilterDescription, FilterExtention
        If .Show <> -1 Then Exit Function
        GetFilePath = .SelectedItems(1): PS = Application.PathSeparator
    End With
End Function