If you are installing the 32-bit Application Server on an x64-based edition of Windows Server, no additional post-installation steps are required when using the Application Server installer. The installer automatically enables 32-bit execution for the Application Server's application pool.
For manual installations of the 32-bit Application Server in a 64-bit environment, the application pool must be enabled for 32-bit applications. See Application Server Manual Installation Overview for complete information on manually installing the Application Server, including steps on configuring the application pool.