.I am running .Net v1.0.5.6 ASP.Net 2.0.59727 on Windows 2003 server sp2 fully patched as of 10-13-08. We are having difficutly overcoming what seems to be a timeout error. We receive the attached error

The web.config is set executionTimeout="3000", "InProc" timeout="480", IIS session state =240, yet this error happens within an hour.Addtionall in the event logs is the below error:
App: W 'Tue Oct 14 09:23:20 2008': ASP.NET 2.0.50727.0 - " Event code: 3005 Event message: An unhandled
exception has occurred. Event time: 10/14/2008 9:23:20 AM Event time (UTC): 10/14/2008 2:23:20
PM Event ID: 9e4fdd189ba045399665092d0fe49e6e Event sequence: 32 Event occurrence: 5 Event
detail code: 0 Application information: Application domain: /LM/W3SVC/752534/Root-1-128684071768155718
Trust level: Full Application Virtual Path: / Application Path: E:\Mail Server Web
FrontEnd\ Machine name: WEB4 Process information: Process ID: 4212 Process
name: w3wp.exe Account name: NT AUTHORITY\NETWORK SERVICE Exception information:
Exception type: Exception Exception message: Invalid validation token Request information:
Request URL: http://ourdomain/Auth/Default.aspx Request path: /Auth/Default.aspx
User host address: ourip User: ouruser Is authenticated: True Authentication
Type: Forms Thread account name: NT AUTHORITY\NETWORK SERVICE Thread information:
Thread ID: 1 Thread account name: NT AUTHORITY\NETWORK SERVICE Is impersonating: False
Stack trace: at System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage reqMsg,
IMessage retMsg) at System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData,
Int32 type) at Argosoft.MailServer.RemotingInterface.IRemoteAccess.GetFolders(String address, String
token) at Auth_Default.FillFolderList() in e:\Mail Server Web FrontEnd\Auth\Default.aspx.cs:line
99 at Auth_Default.Page_Load(Object sender, EventArgs e) in e:\Mail Server Web FrontEnd\Auth\Default.aspx.cs:line
61 at System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs
e) at System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e) at
System.Web.UI.Control.OnLoad(EventArgs e) at System.Web.UI.Control.LoadRecursive() at System.Web.UI.Page.ProcessRequestMain(Boolean
includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) Custom event details:
"
This forces the user to take the /Auth/Default.aspx out of the url and relogin.
Anyone have a fix for this?
Thanks