To fix the error in the title (permissions issue) you need to right-click the application icon to launch it, at the point when you’re intending to do the update. Being logged in as an admin isn’t enough - you need to launch as an admin.
The other issue that it doesn’t then launch may indicate that you’ve installed an incompatible patch version. In particular, newer patch releases don’t always work with older standalone installations because they might need additional dependencies.
But I tried to install PsychoPy v3.0.0b10 onto PsychoPy v3.0.0b9. The difference between them shouldn’t be that big. I solved it now by upgrading using the Standalone-Installer. But now I get the problem stated here (Issue 5523).