pyinstaller [ErrNo 22]

I had the same issues but found these other solutions did not fix the problem. I did however find a fix as follows:

First, my situation may be a little different to the OP as I'm using the Anaconda Python distribution on Windows 7, and used the conda command line too to install pywin32, and then used pip to install pyinstaller.

I found the same IOError was preceded by this earlier error message in the pyinstaller output log:

ImportError: No system module 'pywintypes' (pywintypes27.dll)  

The solution that fixed both errors was to copy the DLL files:

pywintypes27.dll
pythoncom27.dll 

sitting in: C:\<anaconda-dir>\Lib\site-packages\win32

to C:\<anaconda-dir>\Lib\site-packages\win32\lib

Where <anaconda-dir> will either be your root Anaconda directory:

C:\Users\<username>\AppData\Local\Continuum\Anaconda\ by default,

or an environment you have set up e.g.

C:\Users\<username>\AppData\Local\Continuum\Anaconda\envs\<environment-name>

A came across this answer thanks to Tompa here, who found it solved a similar problem in py2exe.