By default, IIS running on a 64 bit computer does not support running a 32 bit application. However, you can change the setting in an Application Pool under which the application is running by setting the ‘Enable 32-bit Applications‘ to true. 

In IIS, I created a new web-site and change the application pool to enable 32-bit application to support my 32 bit application.

While accessing the apppplication i got the  "HTTP Error 503. The service is unavailable" error.

Also Identified that the application pool was stopped repeatedly when i tried to access the  application. Finally got the below error from event viewer.

The Module DLL ‘C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\15\isapi\spnativerequestmodule.dll’ could not be loaded due to a configuration problem. The current configuration only supports loading images built for a x86 processor architecture. The data field contains the error number. To learn more about this issue, including how to troubleshooting this kind of processor architecture mismatch error, see http://go.microsoft.com/fwlink/?LinkId=29349.

Solution:

Run the following command in Windows Command Prompt. 


"%systemroot%\system32\inetsrv\AppCmd.exe" set config -section:system.webServer/globalModules
/[name='SPNativeRequestModule'].preCondition:integratedMode,bitness64

This  will solve the problem to load SPNativeRequestModule when the application pool is running in Integrated Mode and 64-bit application mode.

Hope the issue solved !!