On 64-bit hosts, with guest operating systems that support both 32-bit and 64-bit hardware, the Workstation interface does not provide a way to install the guest as a 32-bit operating system. Some guest operating systems will automatically install as 64-bit systems when the host machine is 64-bit. If you want to install such an operating system as a 32-bit guest on a 64-bit host, add the following line to the virtual machine's configuration (.vmx) file:
monitor_control.disable_longmode=1