Response.Redirect doesn't work in any processing is done on aspx page

since you're doing the response.redirect when the page posts back, there are a couple things we can look at.  Your best bet is to post the code and we can take a look and probably give you an answer very quickly.

Hai,

Try encapsulating all code in the Function:
Private Sub Page_Load(
.....
with:

If Not Page.IsPostBack Then
.....
End if

Bye
Ajai

The procedure calls to load the data are in a "If Not IsPostBack" statement in the Page_Load event as follows:

Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        If Not IsPostBack Then
            LoadProviderNames()
            LoadProviderSSNs()
            LoadProviderTINs()
        End If
    End Sub

These load 3 respective dropdown lists using System.Data.SQLClient methods to a SQL Server 2000 database:
(all three procedures are identical, substituting the ddlProviderName.* with ddlProviderSSN.* and ddlProviderTIN.* and the called views as SSNLookupProv and TINLookupProv)

      Dim sConnection As String = GetConnectionString(giConnTypeNP, Server.MapPath(gsConnFilePath))
        Dim conn As New SqlConnection(sConnection)
        Dim cmd As SqlCommand
        Dim myReader As SqlDataReader
        Dim sSQL As String = ""
        Try
            conn.Open()
            'fill the providername ddl
            sSQL = "Select Name from NameLookUp"
            cmd = New SqlCommand(sSQL, conn)
            myReader = cmd.ExecuteReader
            If myReader.HasRows Then
                ddlProviderName.Items.Clear()
                ddlProviderName.Items.Add(" ")
                Do While myReader.Read
                    ddlProviderName.Items.Add(myReader.GetValue(0))
                Loop
            End If
            cmd.Dispose()
            cmd = Nothing
            myReader.Close()
            myReader = Nothing
            conn.Close()

            If conn.State <> ConnectionState.Closed Then
                conn.Close()
                conn.Dispose()
                conn = Nothing
            End If
        Catch ex As Exception
            If conn.State <> ConnectionState.Closed Then
                conn.Close()
                conn.Dispose()
                conn = Nothing
            End If
            Session("Exception") = CleanException(ex.Message.ToString)
            Response.Redirect("errorpage.aspx")
        End Try

And the page loads fine, however when you click on the image button control ibtn0, no work is done and the get the "Page cannot be displayed" http error page is displayed. It will not even hit a breakpoint in the ibtn0_Click event unless I use a simple html <A href> link instead of a button control. Note that ALL other button events work as expected everywhere else in the program and on this page, unless any processing is done as shown in the procedure above. One procedure call and everything is fine, more than one procedure call and nothing. Currently, these are the only 4 procedures addressed on this aspx page of the program.
This is the ibtn0 event:

    Private Sub ibtn0_Click(ByVal sender As System.Object, ByVal e As System.Web.UI.ImageClickEventArgs) Handles ibtn0.Click
        Response.Redirect("ProviderEdit.aspx")
    End Sub

Like I said, I had this occur a few weeks ago, but it mysteriously went away & I never had another problem till now. I am at a total loss to explain or fix it and have found no reference to this type of problem. Any help is greatly appreciated.
Thanks!

This didn't help, but the standard .net button controls work correctly. I've been through IIS and verified security permissions on the folders and they are correct. I'm to the point of starting a new project & redoing the code from scratch just to see if there is something I inadvertantly screwed up. Thanks.