You need to convert to the correct type
in C# it's
Lbl_Biller.Text = (string)Session("UserCode") ... ( equiv in VB is CType I think)... but that sometimes fails saying "invalid Cast"
Lbl_Biller.Text = Session("UserCode").ToString() ..... usually works
Lbl_Biller.Text = Convert.ToString(Session("UserCode")) has never failed as far as I can remember