Problem downloading a file in ASP.NET

[Andrix]

HI,
I have this code to do an .xls from a data grid, and then download to
the client machine.
In my intranet works excelente. But in the internet, when i click in
the button "Export to Excel" open the download dialog, but ask me to
download the .aspx file (that contain the next code) ??

this app in asp.net is under a SSL connection.

what it could be????

Thanks

Response.Clear()
Response.Buffer = True
Response.ContentType = "application/vnd.xls"

Dim filename As String
filename = .....

Response.AddHeader("content-disposition",
"attachment;filename=" & filename)
Response.Charset = ""

Response.Cache.SetCacheability(HttpCacheability.NoCache)

Me.EnableViewState = False

Dim stringWrite As System.IO.StringWriter = New
System.IO.StringWriter()
Dim htmlWrite As System.Web.UI.HtmlTextWriter = New
HtmlTextWriter(stringWrite)

Me.DataGrid1.AllowPaging = False
Me.CargarDatos("")

Me.ClearControls(Me.DataGrid1)
Me.DataGrid1.RenderControl(htmlWrite)
Response.Write(stringWrite.ToString())
Response.End()

Me.DataGrid1.AllowPaging = True
Me.CargarDatos("")

Me.EnableViewState = True