How to enable ISAPI on Windows 2008 server 64-bit with IIS 7.0

Symptom
Receiving error message "HTTP 500 - Internal server error"

Problem
These steps are required to enable the cognosisapi.dll ISAPI module to run on on Windows 2008 server 64-bit with IIS 7.0

Environment
Windows 2008 server 64-bit

Solution
The cognosisapi.dll ISAPI module is a 32-bit DLL, even when you installed the 64-bit version of Cognos 8.
On 64-bit Windows, 32-bit processes cannot load 64-bit DLLs, and 64-bit processes cannot load 32-bit DLLs. If you want to run 32-bit applications on 64-bit Windows, you have to configure IIS to create 32-bit worker processes.

By default IIS launches Common Gateway Interface (CGI) applications on 64-bit Windows, because CGI applications run in a separate process.

Configuring IIS to run 32-bit Web applications on 64-bit Windows IIS 7.0:

Before you configure IIS to run 32-bit applications on 64-bit Windows, note the following:

* IIS only supports 32-bit worker processes in Worker Process Isolation mode on 64-bit Windows.
* On 64-bit Windows, the 'World Wide Web Publishing' service can run 32-bit and 64-bit worker processes. Other IIS services like the 'IIS Admin' service, the 'SMTP service', the 'NNTP service', and the 'FTP service' run 64-bit processes only.
* On 64-bit Windows, the 'World Wide Web Publishing' service does not support running 32-bit and 64-bit worker processes concurrently on the same server.


Steps:

1. Open Internet Information Services (IIS) Manager and select 'Application Pools'.
2. Select your application pool for the Cognos 8 Virtual Directories, or if you have not defined an application pool, select the 'DefaultAppPool' and on the right-hand side of the window click on ‘Set Application Pool Defaults’.
3. Under 'General' ensure that 'Enable 32-bit applications' is set to 'True'.
4. Restart IIS.
5. Continue to configure IIS 7.0 for the Cognos 8 Gateway

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