COM object with CLSID(Some number) is either not valid or not registered

Hi Experts

I am using SQLDMO COM object in my VB.Net application. the installer of my application is working fine on many client machines but it generates following error on click button on one client machine

COM object with CLSID(Some number) is either not valid or not registered.

following code runs on click button
           txtDatabase.Items.Clear()
            Dim srv As SQLDMO.SQLServer
            srv = New SQLDMO.SQLServerClass
            Try
                srv.Connect(txtServer.Text, txtUser.Text, txtPass.Text)

                Dim db As New SQLDMO.Database
                For Each db In srv.Databases
                    If db.Name <> Nothing Then
                        Me.txtDatabase.Items.Add(db.Name)
                    End If
                Next

            Catch ex As Exception
                MsgBox(ex.Message, MsgBoxStyle.Information, "UpdateUtility")
            End Try

its very urgent

thanks,
imrancs