GridView error on Edit link clicked

I am using Visual studio 2010, targeting 3.5 framework with MySQL database as the backend.

My gridview loads fine, I click the 'Edit' link and it allows me to edit.  Once I hit the 'Update' link I keep getting the following error, "Index was out of range. Must be non-negative and less than the size of the collection. Parameter name: index"

The line it  points to is in gvCourses_RowUpdating --> Dim iCourseID As Integer = Int32.Parse(gvCourses.DataKeys(e.RowIndex).Value.ToString)

Below is the code I am using.   Does anyone know see why I keep getting this?

Html code

<asp:GridView ID="gvCourses" runat="server"
        AutoGenerateColumns="false"
        DataKeyField="course_id"
        HeaderStyle-CssClass="dgStyle"
        OnPageIndexChanging="gvCourses_PageIndexChanging"
        OnPageIndexChanged="gvCourses_PageIndexChanged"
        OnRowCancelingEdit="gvCourses_RowCancelingEdit"
        OnRowDataBound="gvCourses_RowDataBound"
        OnRowDeleting="gvCourses_RowDeleting"
        OnRowEditing="gvCourses_RowEditing"
        OnRowUpdating="gvCourses_RowUpdating"
        OnSorting="gvCourses_Sorting" OnSorted="gvCourses_Sorted"><Columns><asp:CommandField ShowEditButton="true" /><asp:CommandField ShowDeleteButton="true" /><asp:BoundField DataField="course_id" HeaderText="ID" ReadOnly="true" /><asp:BoundField DataField="course_name" HeaderText="Course Name" /><asp:BoundField DataField="course_desc" HeaderText="Course Desc" /><asp:BoundField DataField="course_order" HeaderText="Course Order" /><asp:BoundField DataField="course_folder" HeaderText="Course Folder" ReadOnly="true" /><asp:TemplateField HeaderText="Course Certificate"><ItemTemplate><%# Container.DataItem("course_certificate")%></ItemTemplate><EditItemTemplate><asp:DropDownList id="ddlCourseCertificate" runat="server" DataTextField="CourseCertificate" DataValueField="CourseCertificateVal"></asp:DropDownList></EditItemTemplate></asp:TemplateField><asp:BoundField DataField="course_entry_dt" HeaderText="Entry Dt" ReadOnly="true" /></Columns></asp:GridView>

Code behind:

Imports System.Web.Security
Imports System.Security.Principal
Imports System.IO

Partial Class admin_courses
    Inherits System.Web.UI.Page

    Dim oFn As clsFunctions = New clsFunctions
    Protected dvwCourseCertificates As DataView = New DataView()

    Protected Sub Page_Load(sender As Object, e As System.EventArgs) Handles Me.Load
        If User.Identity.IsAuthenticated = True Then
            Dim id As FormsIdentity = CType(HttpContext.Current.User.Identity, FormsIdentity)
            Dim ticket As FormsAuthenticationTicket = id.Ticket
            Dim userData As String = ticket.UserData
            Dim roles() As String = userData.Split(Microsoft.VisualBasic.ChrW(44))
            ' Create a new Generic Principal Instance and assign to Current User
            HttpContext.Current.User = New GenericPrincipal(id, roles)

            Dim objFormsID As FormsIdentity
            objFormsID = User.Identity

            'Had issues with activated users not passing the right userdata this signs you out if so
            If objFormsID.Ticket.UserData = "0" Then
                Session.Abandon()
                FormsAuthentication.SignOut()
                Response.Redirect("/login.aspx")
            End If

            'Finally check if admin user
            If Session("User_Role") <> "SUPER USER" Then
                Session.Abandon()
                FormsAuthentication.SignOut()
                Response.Redirect("/login.aspx")
            End If

            If Not IsPostBack() Then
                gvCourses.AllowPaging = True
                gvCourses.PageSize = 25
                gvCourses.AllowSorting = True
                ViewState("SortExpression") = "course_order ASC"

                sbLoadPage()
            End If
        Else
            Session.Abandon()
            FormsAuthentication.SignOut()
            Response.Redirect("/login.aspx")
        End If

    End Sub

#Region " sbLoadPage() "
    Private Sub sbLoadPage()
        'load the gridview control
        Dim ds As DataSet = oFn.GetSQLData("SELECT * FROM `course`")

        If Not (ds Is Nothing) Then
            Dim dvCourses As DataView = ds.Tables(0).DefaultView
            dvCourses.Sort = ViewState("SortExpression").ToString()

            gvCourses.DataSource = dvCourses
            gvCourses.DataBind()
        End If

    End Sub
#End Region

    Sub PopulateDropdownlist()
        Dim dtCourses As DataTable = New DataTable()
        dtCourses = oFn.CertificatesInDataTable(Server.MapPath("../certificates"))
        dvwCourseCertificates = New DataView(dtCourses)
    End Sub

    Protected Sub gvCourses_PageIndexChanged(sender As Object, e As System.EventArgs) Handles gvCourses.PageIndexChanged
        sbLoadPage()
    End Sub

    Protected Sub gvCourses_PageIndexChanging(sender As Object, e As System.Web.UI.WebControls.GridViewPageEventArgs) Handles gvCourses.PageIndexChanging
        gvCourses.PageIndex = e.NewPageIndex
        gvCourses.EditIndex = -1
        gvCourses.SelectedIndex = -1
        'sbLoadPage()
    End Sub

    Protected Sub gvCourses_RowCancelingEdit(sender As Object, e As System.Web.UI.WebControls.GridViewCancelEditEventArgs) Handles gvCourses.RowCancelingEdit
        ' Exit edit mode. 
        gvCourses.EditIndex = -1

        ' Rebind the GridView control to show data in view mode. 
        sbLoadPage()

    End Sub

    Protected Sub gvCourses_RowDataBound(sender As Object, e As System.Web.UI.WebControls.GridViewRowEventArgs) Handles gvCourses.RowDataBound

        Dim drv As DataRowView = CType(e.Row.DataItem, DataRowView)

        If (e.Row.RowType = DataControlRowType.DataRow) AndAlso (e.Row.RowState = DataControlRowState.Normal OrElse e.Row.RowState = DataControlRowState.Alternate) Then
            ' Add client-side confirmation when deleting. 
            DirectCast(e.Row.Cells(1).Controls(0), LinkButton).Attributes("onclick") = "if(!confirm('Are you certain you want to delete this course?')) return false;"
        End If

        'Load dropdown in Edit mode
        If (e.Row.RowType = DataControlRowType.DataRow) AndAlso (e.Row.RowState = DataControlRowState.Edit Or e.Row.RowState = DataControlRowState.Alternate + DataControlRowState.Edit) Then
            Dim ddlCourseCertificate As DropDownList = e.Row.FindControl("ddlCourseCertificate")
            Dim iRecruiter_ID As Integer = e.Row.Cells(2).Text

            Dim dtCourses As DataTable = New DataTable()
            dtCourses = oFn.CertificatesInDataTable(Server.MapPath("../certificates"))
            PopulateDropdownlist()

            ddlCourseCertificate.DataSource = dtCourses
            ddlCourseCertificate.DataTextField = "CourseCertificate"
            ddlCourseCertificate.DataValueField = "CourseCertificateVal"
            ddlCourseCertificate.DataBind()

            Dim iLoop As Integer = 0
            For Each dRow As DataRow In dtCourses.Rows
                If dRow.Item(0) = drv("course_certificate") Then
                    ddlCourseCertificate.Items(iLoop).Selected = True
                Else
                    ddlCourseCertificate.Items(iLoop).Selected = False
                End If
                iLoop += 1
            Next
        End If
    End Sub

    Protected Sub gvCourses_RowDeleting(sender As Object, e As System.Web.UI.WebControls.GridViewDeleteEventArgs) Handles gvCourses.RowDeleting
        'code that deletes row
        Dim sCourse_ID As String = gvCourses.Rows(e.RowIndex).Cells(2).Text
        oFn.GetSQLData("DELETE FROM course WHERE course_id = " & sCourse_ID)
        sbLoadPage()
    End Sub

    Protected Sub gvCourses_RowEditing(sender As Object, e As System.Web.UI.WebControls.GridViewEditEventArgs) Handles gvCourses.RowEditing
        gvCourses.EditIndex = e.NewEditIndex
        sbLoadPage()
    End Sub

    Protected Sub gvCourses_RowUpdating(sender As Object, e As System.Web.UI.WebControls.GridViewUpdateEventArgs) Handles gvCourses.RowUpdating

        'e.Keys, e.NewValues, and e.OldValues are only populated if using DataSourceID    
        Dim iCourseID As Integer = Int32.Parse(gvCourses.DataKeys(e.RowIndex).Value.ToString)
        Dim txtCourse_ID As TextBox = DirectCast(gvCourses.Rows(e.RowIndex).Cells(2).Controls(0), TextBox)

        gvCourses.EditIndex = -1
        sbLoadPage()
    End Sub

    Protected Sub gvCourses_Sorted(sender As Object, e As System.EventArgs) Handles gvCourses.Sorted
        sbLoadPage()
    End Sub

    Protected Sub gvCourses_Sorting(sender As Object, e As System.Web.UI.WebControls.GridViewSortEventArgs) Handles gvCourses.Sorting
        Dim strSortExpression As String() = ViewState("SortExpression").ToString().Split(" "c)


        ' If the sorting column is the same as the previous one,  
        ' then change the sort order. 
        If strSortExpression(0) = e.SortExpression Then
            If strSortExpression(1) = "ASC" Then
                ViewState("SortExpression") = Convert.ToString(e.SortExpression) & " " & "DESC"
            Else
                ViewState("SortExpression") = Convert.ToString(e.SortExpression) & " " & "ASC"
            End If
        Else
            ' If sorting column is another column,   
            ' then specify the sort order to "Ascending". 
            ViewState("SortExpression") = Convert.ToString(e.SortExpression) & " " & "ASC"
        End If

        gvCourses.EditIndex = -1
        gvCourses.SelectedIndex = -1
    End Sub
End Class