Do you have Cubase 9.5.21 and Cubase 9.5.30 installed side by side? If yes, try to copy the video component from Cubase 9.5.21 to Cubase 9.5.30 application, please.
It’s a wired message. Cubase is not using QuickTime video engine since Cubase 9.0.40. The message looks like the old (Cubase 9.0.30) video component is used.