Paul,

Here is my web.config file (I stripped out my assemblies, etc.) and I did not re-load dlls during this testing:

<?xml version="1.0"?>
<!-- 
    Note: As an alternative to hand editing this file you can use the 
    web admin tool to configure settings for your application. Use
    the Website->Asp.Net Configuration option in Visual Studio.
    A full list of settings and comments can be found in 
    machine.config.comments usually located in 
    \Windows\Microsoft.Net\Framework\v2.x\Config 
-->
<configuration>
	<configSections>
		<section name="databaseSets" type="System.Configuration.NameValueSectionHandler, 
         System, Version=1.0.3300.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"/>
		<section name="databases" type="System.Configuration.NameValueSectionHandler, 
         System, Version=1.0.3300.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"/>
	</configSections>
	<connectionStrings>
		<add name="xxxConn" connectionString="Server=xxx;Integrated Security=true;Database=TradeMgmt"/>
	</connectionStrings>
	<system.web>

    <sessionState mode="InProc" cookieless="false" timeout="60"/>
		<!-- 
            Set compilation debug="true" to insert debugging 
            symbols into the compiled page. Because this 
            affects performance, set this value to true only 
            during development.
        -->
		<httpHandlers>
			<add path="Telerik.ReportViewer.axd" verb="*" type="Telerik.ReportViewer.WebForms.HttpHandler, Telerik.ReportViewer.WebForms, Version=2.0.1.0, Culture=neutral, PublicKeyToken=a9d7983dfcc261be" validate="true"/>
		</httpHandlers>
		<compilation debug="false">
			<assemblies></assemblies>
		</compilation>
		<pages>
			<namespaces>
				
			</namespaces>
			<controls>
				
			</controls>
		</pages>
		<!--
            The <authentication> section enables configuration 
            of the security authentication mode used by 
            ASP.NET to identify an incoming user. 
        -->
		<authentication mode="Forms">
          <forms timeout="60" slidingExpiration="true" />
    </authentication>

		<!--
            The <customErrors> section enables configuration 
            of what to do if/when an unhandled error occurs 
            during the execution of a request. Specifically, 
            it enables developers to configure html error pages 
            to be displayed in place of a error stack trace.

        <customErrors mode="RemoteOnly" defaultRedirect="GenericErrorPage.htm">
            <error statusCode="403" redirect="NoAccess.htm" />
            <error statusCode="404" redirect="FileNotFound.htm" />
        </customErrors>
        -->
	</system.web>
	<appSettings>
		<!-- Event Log, Trace Log and Transaction Log settings:
	1. The EventLog Level setting (options are "Error", "Warning", "Info", and "Verbose"
	2. The name of the machine on which the event log resides, default is "." (local machine)
	3. The name of the log
	-->
		<add key="EventLog\Level" value="Verbose"/>
		<add key="EventLog\Machine" value="."/>
		<add key="EventLog\Name" value="Application"/>
		<add key="TraceLog\Machine" value="."/>
		<add key="TraceLog\Name" value="Application"/>
		<add key="TransactionLog\Machine" value="."/>
		<add key="TransactionLog\Name" value="Application"/>
		<!-- If set to false, indicates the application is not localized,
	and uses hard-coded strings for displaying messages and
	for user interface text. If true, specifies the application uses
	mmMessageMgr to data-drive application text.
	-->
		<add key="LocalizeApp" value="false"/>
		<!-- Specifies the primary key of the default application language
	(for localization purposes). Only used when LocalizeApp="true"
	-->
		<add key="DefaultLanguage" value="1"/>
		<!-- Specifies the database key for application messages
	This key doesn't need to be specified if there is only one
	database in your application specified in the <databases> element.
	Only used when LocalizeApp="true"
	-->
		<add key="MessageDatabaseKey" value=""/>
		<!-- Specifies the database key for application security tables
	This key doesn't need to be specified if there is only one
	database in your application specified in the <databases> element
	-->
		<add key="SecurityDatabaseKey" value=""/>
	</appSettings>
	<databases>
		<add key="xxx" value="Data Source=xxx;Initial Catalog=TradeMgmt;Integrated Security=True"/>
		<add key="TradeMgmt\DataAccessClass" value="DataAccessSql"/>
	</databases>
</configuration>

>>Unfortunately, the changes you suggested have not had an effect. The timeout still occurs at about 20 minutes. I will continue to research, but this is a tedious process to test, as setting it up and testing takes time and can only be done after hours.
>>
>>If you have any other suggestions, I would be happy to hear. If not, thanks again for your help.
>>
>
>Why don't you post your web.config file (just remember to strip out any sensitive info). You didn't happen to be changing the web.config at the same time (or dropping in new DLL's, etc)? If so, that causes ASP.NET to unload/reload (losing the session).