I have a .mov file I want to cut down in FCP, but it's not letting me open it. Why not? It produces .mov, why won't it open it? What do I need to do? Oh, it's 4.0.1. Is there a codec?

The error reads: "Does not support frame rate or file extension." How wonderul. I need this video asap, so any help would be great.

Sounds like the framerate doesn't match the project settings. You need to open a project that matches the framerate of the video.

.mov just means it is a Quicktime file. There are dozens of codecs that Quicktime supports and includes. So you have a QT file, but it might be a codec that FCP does not work with. Not all codecs are editing codecs. And FCP doesn't edit non-broadcast frame rates. 15fps, 10fps...unsupported. 23.98, 24, 29.97, 59.94....those are supported.

Open the file in QT and get the Movie Properties.