Why I can not open remote Office document in browser?(vb.net)

Hello,everybody.

I have a problem like this:
I want to click a doc hy-link in the client browser to call local office application and open an office document saved in the server,like Word or Visio.but it is always wrong.

I use VB.NET, and the codes:

'WebForm1.aspx
Imports OWSSUPP 'an Office 2003 DLL

Public Class WebForm1
Inherits System.Web.UI.Page

Dim openDoc As New OWSSUPP.COWSNewDocumentClass

Private Sub btnEditFile_Click() Handles btnEditFile.Click
Dim bFileOpened As Boolean
Try
bFileOpened = Me.openDoc.ViewDocument("http://localhost/UpFiles/1.doc")
Catch ex As Exception
Me.lstMsg.Items.Add(ex.ToString) 'can not catch anything
End Try

If bFileOpened = True Then
Me.lstMsg.Items.Add("File Opened Right!")
Else
Me.lstMsg.Items.Add("File Opened Wrong!") 'always show this
End If

End Sub

The OWSSUPP.DLL class browser:
Interop.OWSSUPP
+{}OWSSUPP
+Interface:COWSNewDocument
+Class:COWSNewDocumentClass
+Interface:COWSStssyncHandler
+Class:COWSStssyncHandlerClass
+Interface:OWSExcelLauncher

My Server:
Windows Server 2003 Enterprise Edition and Server Pack 1;
Visual Studio .NET 2003 Enterprise Architect
IIS6.0 and local disk format is NTFS
the virtual dir is Read and Write

My Browser:
Internet Explorer 6.0.3790.1830 SP1

Thanks everybody here!