I fresh installed Python37-32 on win10-64 All requirements seem to be satisfied and my hello world python file is executing
if __name__ == \'__main__\' :
Download pyinstaller and install from source instead using pip.
python setup.py install
Then if your system is 64bit, the 64bit bootloader is built altough the python37-32 needs 32 bit bootloader.
In the source cd bootloader and run python ./waf all --target-arch=32bit as explained here
Then copy run.exe from build folder to pyinstaller 32bit bootloader folder.
An issue has been opened on pyinstaller github.