[求助].Net中用宏控制SourceSafe

Boeing747

[Code]
Dim fullname As String = ActiveDocument().FullName()
Dim fname As String = ActiveDocument().Name()
        
Dim scc As SourceControl = DTE.SourceControl
If Not (scc Is Nothing) Then
   If scc.IsItemUnderSCC(fullname) Then
       If Not scc.IsItemCheckedOut(fullname) Then
          Dim bCheckOut As Boolean = scc.CheckOutItem(fname)
       End If
    End If
End If
[/Code]
Visual Studio .NET 2003中，如上，bCheckOut返回True，但文档不能check out.

哪位指点一下？