I'm working on a project in Final Cut 7 with progressive footage shot at 29.97 fps. All the footage was transcoded to ProRes 422 .MOV files. I subsequently ran a couple clips through Compressor to slow them down using the frame controls tool and setting the duration to 300% of source. I used the same settings for three clips. Two of them imported into FCP just fine. The third continues giving me this error every time I try to import it -- "File error: 1 File recognized, 0 access denied, 1 unknown."
I took the original clip (normal speed) and ran it through Compressor again with the same results.
Its possible that the problem clip is somehow corrupt. What happens if you try importing it into FCP directly at normal speed? If that works perhaps export it as a new clip and try that one in Compressor. If it does not work you know the clip is the issue. Might be worth trying to open it in MPEG streamclip or QT7 but this may be problematic also depending on the issue.