Sys.InvalidOperationException error, TabContainer was not found.

Hi,

I have a really simple page that uses the gmap.dll control from subgurim. When I place the control inside a tabcontainer, I receive the following error:

<div style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;" id="_mcePaste">Line: 4670</div> <div style="position: absolute; left: -10000px; top: 0px; width: 1px; height: 1px; overflow-x: hidden; overflow-y: hidden;" id="_mcePaste">Error: Sys.InvalidOperationException: Component 'ctl00_ContentPlaceHolderMain_TabContainer1' was not found.</div>

Line: 4670

Error: Sys.InvalidOperationException: Component 'ctl00_ContentPlaceHolderMain_TabContainer1' was not found.

The strange thing is that I only get the error upon a refresh of the page and only remotely, never when I test the page in Visual Web Developer locally.

This is the code I use:

<%@ Page Title="" Language="VB" MasterPageFile="~/MasterPage.master" AutoEventWireup="false" CodeFile="Default4.aspx.vb" Inherits="Default2" %><%@ Register assembly="AjaxControlToolkit" namespace="AjaxControlToolkit" tagprefix="asp" %><%@ Register assembly="GMaps" namespace="Subgurim.Controles" tagprefix="cc1" %><asp:Content ID="Content1" ContentPlaceHolderID="ContentPlaceHolderMain" Runat="Server"><asp:TabContainer ID="TabContainer1" runat="server" ActiveTabIndex="0"><asp:TabPanel runat="server" HeaderText="TabPanel1" ID="TabPanel1"><ContentTemplate><cc1:GMap ID="GMap1" runat="server" Key="<Key>" /></ContentTemplate></asp:TabPanel></asp:TabContainer></asp:Content>

Can anybody tell me what is causing this and how I can solve it? Thanks!