ASP.NET

Dim connectionString As String = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & strNewPath & ";Extended Properties=""Excel 8.0;HDR=Yes;IMEX=2"""

<customErrors defaultRedirect="~/Error.aspx" mode="RemoteOnly">
  <error statusCode="404" redirect="~/Error.aspx" />
  <error statusCode="500" redirect="~/Error.aspx" />
</customErrors>

Sub Application_Error(ByVal sender As Object, ByVal e As EventArgs)
    ' Code that runs when an unhandled error occurs
    ' gets the error occured
    Dim ex As Exception = Server.GetLastError().GetBaseException()
    Try
        ' checks if the event source is registered
        If Not System.Diagnostics.EventLog.SourceExists(".NET Runtime") Then
            System.Diagnostics.EventLog.CreateEventSource(".NET Runtime", "Application")
        End If

        'log the details of the error occured
        Dim log As New System.Diagnostics.EventLog()
        log.Source = ".NET Runtime"
        log.WriteEntry([String].Format(vbCr & vbLf & vbCr & vbLf & "Application Error" & vbCr & vbLf & vbCr & vbLf + "MESSAGE: {0}" &
                                       vbCr & vbLf + "SOURCE: {1}" & vbCr & vbLf + "FORM: {2}" & vbCr & vbLf + "QUERYSTRING: {3}" &
                                       vbCr & vbLf + "TARGETSITE: {4}" & vbCr & vbLf + "STACKTRACE: {5}" & vbCr
                                       & vbLf, ex.Message, ex.Source, Request.Form.ToString(), Request.QueryString.ToString(), ex.TargetSite, _
         ex.StackTrace), System.Diagnostics.EventLogEntryType.[Error])

        Server.ClearError()
    Catch
        ' in case of exception occured in log
        Server.ClearError()
    End Try
    Server.ClearError()
    Response.Redirect(String.Format("Error.aspx?aspxerrorpath={0}", Request.Url.PathAndQuery))
End Sub