Gridview with ConfirmButtonExtender & ModalPopupExtender issue

Hi all:

I have a web application that allows the user to download files, once they say ok to the terms and conditions.  This works, but there's an issue where sometimes, the CommandArgument of the LinkButton holds an "old" value.  Has anyone come across this?  I've spend about 3 hours troubleshooting and searching, and at this point I'm reaching out for some ideas.  Here's my .aspx code:

<asp:GridView ID="gv_dlfilelisting" runat="server" DataSourceID="dllistDS" BorderStyle="None" AutoGenerateColumns="false"
        DatakeyNames="id" GridLines="None" CellPadding="7" AllowPaging="true" PageSize="15"><AlternatingRowStyle BackColor="White" /><Columns><asp:BoundField DataField="id" HeaderText="ID" 
                InsertVisible="False" ReadOnly="True" SortExpression="id" 
                Visible="False" /><asp:TemplateField><ItemTemplate><asp:Image ID="imgDL" runat="server" ImageUrl="~/i/globe_download_16.png"></asp:Image></ItemTemplate><EditItemTemplate></EditItemTemplate><FooterTemplate></FooterTemplate></asp:TemplateField><asp:TemplateField HeaderText="File Description" HeaderStyle-HorizontalAlign="Left"><ItemTemplate><asp:LinkButton ID="lnkCategory" runat="server" Width="300px" CommandName="dlFile" CommandArgument='<%# Eval("filepath")%>'><%# Eval("filedesc")%></asp:LinkButton><asp:ConfirmButtonExtender ID="ConfirmButtonExtender1" runat="server" TargetControlID="lnkCategory" DisplayModalPopupID="ModalPopupExtender1"></asp:ConfirmButtonExtender><asp:ModalPopupExtender ID="ModalPopupExtender1" runat="server" TargetControlID="lnkCategory" PopupControlID="Panel1" OkControlID="agreeButton" 
                        CancelControlID="noButton" OnOkScript="" BackgroundCssClass="modalBackground" ></asp:ModalPopupExtender></ItemTemplate><EditItemTemplate><asp:TextBox ID="tbfileDesc" runat="server" Text='<%# Bind("filedesc")%>'></asp:TextBox></EditItemTemplate></asp:TemplateField><asp:BoundField DataField="filesize" HeaderText="Size" HeaderStyle-HorizontalAlign="Right" ItemStyle-HorizontalAlign="Right" /><asp:TemplateField ShowHeader="False"><ItemTemplate><asp:ImageButton ID="btnEditRow" runat="server" CausesValidation="True" ToolTip="Edit"
                        CommandName="Edit" ImageUrl="~/i/EditTableHS.png" Text="Edit" />&nbsp;<asp:ImageButton ID="btnDeleteRow" runat="server" Text="Delete" CommandName="Delete" ToolTip="Delete" ImageUrl="~/i/trash_16.png"
                            OnClientClick="return confirm('Are you sure you want to delete this file?');" /></ItemTemplate><EditItemTemplate><asp:ImageButton ID="btnSaveRow" runat="server" CausesValidation="True" ToolTip="Save"
                        CommandName="Update" ImageUrl="~/i/Save_16.png" Text="Update" />&nbsp;<asp:ImageButton ID="btnCancelRow" runat="server" CausesValidation="False" ToolTip="Cancel"
                        CommandName="Cancel" ImageUrl="~/i/undo_16.png" Text="Cancel" /></EditItemTemplate><HeaderStyle HorizontalAlign="Left" /><ItemStyle HorizontalAlign="Left" VerticalAlign="Top" /></asp:TemplateField></Columns><HeaderStyle BackColor="#3a4f63" Font-Bold="True" ForeColor="White" /><RowStyle BackColor="#E3EAEB" /><EmptyDataTemplate>No files found.</EmptyDataTemplate></asp:GridView></p><asp:Panel ID="Panel1" runat="server" style="display:none"  CssClass="modalPopup"><div align="center" style="padding-left:5px"><h3>Geomatics</h3>
            I have read and agree to the terms of use as described in the User Agreement on this page.</div><br /><br /><div align="center"><asp:Button ID="agreeButton" runat="server" Text="I agree" /><asp:Button ID="noButton" runat="server" Text="Do not agree" /></div><h5 align="center">User Agreement</h5><p style="padding-left:5px"><asp:GridView ID="GridView1" runat="server" DataSourceID="agreementDS" AutoGenerateColumns="False" GridLines="None" 
            ShowHeader="False"><Columns><asp:BoundField DataField="agreeDescription" SortExpression="agreeDescription" HtmlEncode="false" /></Columns></asp:GridView>

And here is my code behind:

    Protected Sub gv_dlfilelisting_RowCommand(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewCommandEventArgs) Handles gv_dlfilelisting.RowCommand

        If e.CommandName = "dlFile" Then

            Response.Redirect(e.CommandArgument.ToString())

        End If

    End Sub

It's a fairly simple concept, and if I comment out the ConfirmButtonExtender and ModalPopupExtender, the issues goes away.  But, I can't do that.  The user must say yes to the agreement, so I need to get this corrected.  Any help is greatly appreciated.