importing QT movie and getting PCP video-av1 file not found

You have to give us more information.

What camera or application created the file?

What exactly is the Codec of the file? (Quicktime is a somewhat general term)

x

I suspect you're trying to import a reference quicktime where the media that the file is referencing is missing.

Here's a user tip explaining what a reference quicktime is and why these kind of problems occur.

Reference vs Selfcontained Quicktimes - definitions and pros and cons

I'm with Michael....he hit the nail on the head.