It obviously doesn't like the "spaces" in your directory path.

Remove the spaces, or propose a pull request that solves this "auto-inflicted" problem.

Its just strange that I haven't had this problem with previous distribution of WInpython in the same directory.
What is it that causes this problem?

until this release, the code behind the icons was coded in NSIS script, a technical debt and code you can't tweak on your installation.
Now the icon just call a .bat script, here "scripts\ipython_notebook.bat".

Fact is I don't understand why I can't make it work but, the simple "scripts\cmd.bat" resists working with a space in the path, since you make the notice.

==> help me fix "scripts\cmd.bat" and it should work again

ok. try this:
change in scripts\cmd.bat:

call %~dp0env_for_icons.bat

per

call "%~dp0env_for_icons.bat"

and in scripts\env_for_icons.bat:

call %~dp0env.bat

per

call "%~dp0env.bat"

you may confirm it works with this simple fixes

@stonebig Thank you very much.
That works