When logging in to Windows Client the following error message is invoked "You do not appear to be able to use this client."

Operating System: Windows XP Pro SP2
OnTime: 2008 Beta

Method:
Had an existing installation of OnTime 2007 v7.02
Installed OnTime 2008 Windows Client and upgraded the database.
Installed the Web Client and the Customer Portal with their own Virtual Directories under "Default Website" and configured them. These operate fine.

Installed the Remote Server, installing only the files.
Moved the Remote Server folder in to folder C:\Inetpub\wwwroot
Created a Virtual Directory for theremote server and pointed it to this folder.
Used the configuration manager to connect to the database using SQL Server Authentication; Connection test was successful.
Generated a Security Token ID and deselected "Require SSL Connection" and copied the Security Token ID.
Set the connection to a direct connection.
Activated OnTime database, saved settings and started Windows Client.
Within OnTime Client opened the DB Management window.
Selected "Remote Connection".
Entered the Remote Server URL.
Pasted in the Security Token ID.
Connection test was successful.
Attempted to log on using Remote Server. The error message reported was invoked.

Opened Windows Event Viewer:

Event Type:    Warning
Event Source:    ASP.NET 2.0.50727.0
Event Category:    Web Event
Event ID:    1309
Date:        25/10/2007
Time:        20:28:01
User:        N/A
Computer:    GRANTVMXPPRO
Description:
Event code: 3005
Event message: An unhandled exception has occurred.
Event time: 25/10/2007 20:28:01
Event time (UTC): 25/10/2007 19:28:01
Event ID: 6adbdb56365d419abe4f37d13aed3524
Event sequence: 4
Event occurrence: 1
Event detail code: 0
 
Application information:
    Application domain: /LM/W3SVC/1/Root/OnTime2008Web-1-128378139191592500
    Trust level: Full
    Application Virtual Path: /OnTime2008Web
    Application Path: c:\inetpub\wwwroot\OnTime2008Web\
    Machine name: GRANTVMXPPRO
 
Process information:
    Process ID: 2512
    Process name: aspnet_wp.exe
    Account name: GRANTVMXPPRO\ASPNET
 
Exception information:
    Exception type: NullReferenceException
    Exception message: Object reference not set to an instance of an object.
 
Request information:
    Request URL: 
    Request path: 
    User host address: 
    User: 
    Is authenticated: False
    Authentication Type: 
    Thread account name: GRANTVMXPPRO\ASPNET
 
Thread information:
    Thread ID: 6
    Thread account name: GRANTVMXPPRO\ASPNET
    Is impersonating: False
    Stack trace:    at Axosoft.OnTimeWeb.common.SessionCacheManager.get_CurrentUser()
   at Axosoft.OnTimeWeb.Global.Session_End(Object sender, EventArgs e)
 
 
Custom event details:

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Please advise what the problem might be?