I have a clean CPS 4.5 installation and run into a strange problem. When I visit the web interface login page, I would get an internal error has occurred error. The event log shows the following whenever this error occurs.
code: 3008
Event message: A configuration error has occurred.
Event time: 10/9/2007 11:56:07 AM
Event time (UTC): 10/9/2007 3:56:07 PM
Event ID: dc2535769fd24e80bcc65338977a195f
Event sequence: 1
Event occurrence: 1
Event detail code: 0
Application information:
Application domain: /LM/W3SVC/1/ROOT/Citrix/AccessPlatform-1-128364189657368327
Trust level: Full
Application Virtual Path: /Citrix/AccessPlatform
Application Path: c:\inetpub\wwwroot\Citrix\AccessPlatform\
Machine name: RAYVCPS45
Process information:
Process ID: 63876
Process name: w3wp.exe
Account name: NT AUTHORITY\NETWORK SERVICE
Exception information:
Exception type: HttpException
Exception message: Could not load file or assembly Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a or one of its dependencies. The system cannot find the path specified.
Request information:
Request URL: http://10.2.248.112/Citrix/AccessPlatform/auth/login.aspx
Request path: /Citrix/AccessPlatform/auth/login.aspx
User host address: 10.7.83.182
User:
Is authenticated: False
Authentication Type:
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.Web.Compilation.BuildManager.ReportTopLevelCompilationException()
at System.Web.Compilation.BuildManager.EnsureTopLevelFilesCompiled()
at System.Web.Hosting.HostingEnvironment.Initialize(ApplicationManager appManager, IApplicationHost appHost, IConfigMapPathFactory configMapPathFactory, HostingEnvironmentParameters hostingParameters)
Custom event details:
For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.
I don know why it is happening. But after I performed a repair of .net framework 2.0, the problem went away.
Hope it helps in case someone else runs into the same problem
Posted by 
Ray, This might be related to IIS is installed after .NET 2.0 is installed. When IIS is installed after .NET 2.0, the ASP .NET v2.0.50727 is not registered in Web Service Extensions. Thus, WI does not run correctly. By repairing .NET 2.0, .NET 2.0 sees you have IIS installed, it will register ASP .NET v2.0.50727 in IIS for you. So, you might want to install IIS first before installing .NET 2.0 which should avoid problems.