After signing into the Web Interface on Citrix Secure Gateway with Trend OfficeScan installed the following error is presented:
"An internal error occurred. Please contact your system administrator." 
Further information can be gained by setting the following parameter in C:\Inetpub\Wwwroot\Citrix\MetaFrame\web.config:
customErrors mode="Off"
This gives the ASP.Net error: 
Request timed out. 
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. 
Exception Details: System.Web.HttpException: Request timed out.
Source Error: 
An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.  
Stack Trace: 
[HttpException (0x80004005): Request timed out.]
In the Application Event Log the following errors are recorded:
Source: Web Interface
Event ID: 0
Description: A critical server error has occurred: System.Web.HttpException: Request timed out.
Source: ASP.NET 2.0.50727.0
Event ID: 1309
Description: 
Event code: 3001 
Event message: The request has been aborted. 
Event time: 4/02/2008 8:36:49 AM 
Event time (UTC): 3/02/2008 11:36:49 PM 
Event ID: 831ba0d8ae524a8ea1f47eba10372779 
Event sequence: 92 
Event occurrence: 1 
Event detail code: 0 
Application information: 
    Application domain: /LM/W3SVC/1/ROOT/Citrix/AccessPlatform-1-128465551246718750 
    Trust level: Full 
    Application Virtual Path: /Citrix/AccessPlatform 
    Application Path: C:\inetpub\wwwroot\Citrix\AccessPlatform\ 
    Machine name: SERVER 
Process information: 
    Process ID: 5368 
    Process name: w3wp.exe 
    Account name: NT AUTHORITY\NETWORK SERVICE 
Exception information: 
    Exception type: HttpException 
    Exception message: Request timed out. 
Request information: 
    Request URL: 
http://localhost/Citrix/AccessPlatform/site/applist.aspx 
    Request path: /Citrix/AccessPlatform/site/applist.aspx 
    User host address: 127.0.0.1 
    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: