Hi,
Since Cubase 9.0.30 (if I’m right), there is no QuickTime engine used anymore. Cubase is using its own video engine. So it’s weird you get this message. I would recommend to reinstall Cubase 9.5 from the full installer to make sure you get the correct video component installed. Then I would recommend to update Cubase to the latest Cubase 9.5.30 version.
Hopefully you can import video after.