PortableApps.com Launcher ignores the 32-bit executable when ProgramExecutable64 is specified but the file didn't exists.
In 64 bit operating system, for the portable app with both 32 bit and 64 bit exe, e.g. 7-Zip Portable, If you delete the 7-Zip64\7zFM.exe (the 64 bit executable file of 7-Zip), You will receive a ERROR message "7-Zip Portable cannot be started. You may wish to re-install to fix this issue.