Problema com UPDATE gridView

Bom dia

tenho uma área restrita de um sistema para editar dados de um gridview associado a um banco de dados.

as funções de editar são as básicas : editar e deletar.
São 4 campos editáveis.

Estou tendo o seguinte problema ao clicar em "update" :

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Código aspx

<%@ Page Title="" Language="vb" AutoEventWireup="false" MasterPageFile="~/Site.Master" CodeBehind="admin.aspx.vb" Inherits="WebApplication2.admin" %>
<asp:Content ID="Content1" ContentPlaceHolderID="HeadContent" runat="server">
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server">

 <h2>Bem vindo, administrador</h2>
 <asp:Label ID="lblMensagem" runat="server"></asp:Label>
 <p>
 <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False">
 <Columns>
 <asp:BoundField DataField="id" HeaderText="ID" ReadOnly="True" />
 <asp:BoundField DataField="nome" HeaderText="Nome" />
 <asp:BoundField DataField="area" HeaderText="Área" />
 <asp:BoundField DataField="ramal" HeaderText="Telefone" />
 <asp:BoundField DataField="eml" HeaderText="Email" />
 <asp:CommandField ShowDeleteButton="True" />
 <asp:CommandField ShowEditButton="True" />
 </Columns>
 </asp:GridView>
 </p>

</asp:Content>

CÓDIGO .vb

Imports System.Data.OleDb
Public Class admin
Inherits System.Web.UI.Page
Dim conn As New OleDb.OleDbConnection
Dim da As New OleDb.OleDbDataAdapter
Dim dp As String = "Provider=Microsoft.ACE.OLEDB.12.0;Persist Security Info=False;"
Dim dbsource As String = "DATA SOURCE = \\ramais.accdb"
Dim olecom As New OleDb.OleDbCommand
Dim dr As OleDb.OleDbDataReader
Dim ds As DataSet = New DataSet
Dim cmd As OleDbCommand
Dim sSQL As String

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

If Session("login") = 0 Then
Response.Redirect("restrito.aspx")
End If

If IsPostBack = False Then
CarregaGrid()
End If

End Sub

Public Sub CarregaGrid()

sSQL = ""

 sSQL = "SELECT FUNCIONARIOS.id, FUNCIONARIOS.nome, FUNCIONARIOS.area, FUNCIONARIOS.Ramal, FUNCIONARIOS.CELULAR, FUNCIONARIOS.eml "
 sSQL = sSQL & "FROM(FUNCIONARIOS) "
 sSQL = sSQL & "ORDER BY FUNCIONARIOS.nome"
 conn = New OleDbConnection(dp & dbsource)
 conn.Open()
 'Try
 da = New OleDbDataAdapter(sSQL, conn)
 'preenche o dataset
 da.Fill(ds, "ramais")
 'exibe os dados no grid
 Me.GridView1.DataSource = ds
 Me.GridView1.DataBind()
 'Finally
 conn.Close()
 End Sub

 Private Sub GridView1_PageIndexChanging(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewPageEventArgs) Handles GridView1.PageIndexChanging
 GridView1.PageIndex = e.NewPageIndex
 CarregaGrid()
 End Sub

 Private Sub GridView1_RowCancelingEdit(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewCancelEditEventArgs) Handles GridView1.RowCancelingEdit
 GridView1.EditIndex = -1
 CarregaGrid()
 End Sub

 Private Sub GridView1_RowDeleting(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewDeleteEventArgs) Handles GridView1.RowDeleting
 DelItem(e.Values.Item(0))
 CarregaGrid()

 End Sub

 Private Sub GridView1_RowEditing(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewEditEventArgs) Handles GridView1.RowEditing
 GridView1.EditIndex = e.NewEditIndex
 CarregaGrid()
 Me.GridView1.Rows.Item(e.NewEditIndex).BackColor = System.Drawing.Color.LightGray
 Me.GridView1.Rows.Item(e.NewEditIndex).ForeColor = System.Drawing.Color.Black
 End Sub

 Private Sub DelItem(ByVal sItemID As String)

 sSQL = ""
 sSQL = " DELETE * FROM FUNCIONARIOS "
 sSQL = sSQL & " WHERE id =" & sItemID
 conn = New OleDbConnection(dp & dbsource)
 conn.Open()
 'Try
 cmd = New OleDbCommand(sSQL, conn)

 dr = cmd.ExecuteReader()

 dr.Close()
 'Finally
 conn.Close()
 'End Try

 End Sub

 Private Sub GridView1_RowUpdating(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewUpdateEventArgs) Handles GridView1.RowUpdating

 UpItem(e.NewValues.Item(1), e.NewValues.Item(2), e.NewValues.Item(3), e.NewValues.Item(4), e.NewValues.Item(5))
 GridView1.EditIndex = -1
 CarregaGrid()

 End Sub
 Private Function UpItem(ByVal sItemID As String, ByVal sItem2 As String, ByVal sItem3 As String, ByVal sItem4 As String, ByVal sItem5 As String)

 Dim sSQL As String
 Dim conn As OleDbConnection
 Dim cmd As OleDbCommand
 Dim dr As OleDbDataReader

 If sItem2 <> "" Then
 sSQL = ""
 sSQL = " UPDATE FUNCIONARIOS SET "
 sSQL = sSQL & " nome = '" & sItem2 & ""
 sSQL = sSQL & " area ='" & sItem3 & " "
 sSQL = sSQL & " ramal ='" & sItem4 & " "
 sSQL = sSQL & " eml ='" & sItem5 & "';"
 sSQL = sSQL & " WHERE id ='" & sItemID & ""
 Response.Write("teste")
 conn = New OleDbConnection(dp & dbsource)
 conn.Open()
 'Try
 cmd = New OleDbCommand(sSQL, conn)
 Dim rowsAffected As Integer = cmd.ExecuteNonQuery()
 dr = cmd.ExecuteReader
 If rowsAffected Then
 Me.lblMensagem.Text = "Atualizado com sucesso"
 Else
 Me.lblMensagem.Text = "Informações incorretas!"
 End If
 dr.Close()
 'Finally
 conn.Close()
 'End Try

 Else
 Me.lblMensagem.Text = "Dados incompletos!"
 End If

 CarregaGrid()
 End Function

End Class
Alguém pode me ajudar, por favor?

Obrigado desde já