iMovie Source Video problems

Hoping someone can help me with this problem... I don't know what happened, so I'm going to provide as much detail as possible.

I've been working on a video in iMovie '11 (on Lion). Everything was taken from one source video clip, which was in its own event.

Last night, I was able to watch the video in iMovie without any problems. That was the last time I successfully played the video.

This morning, I deleted a duplicate of the project (which had been created about a week ago) to free up some space. I also decided to delete some excess video from my source clip (at the very end), so I selected the part I wanted to delete and hit Reject Selection. I then clicked on a 0:01 clip that somehow escaped from the very end and hit Reject again.

I then clicked on the Move Rejected Clips to Trash button and the application (not the computer as a whole) immediately froze. After leaving it for 5-10 minutes without any changes, I decided that it was best to Force-Quit the program and did so. I can't remember perfectly, but I think I might have emptied the Trash too.

In any case, when I re-opened the project, I found that the Event was completely empty. All of the audio and video clips in the timeline displayed the "Source clip is missing" message and triangle.

Here's where I'm stuck, though. I went into the "iMovie Events" folder and clicked on the Event... and the video was still there (all 8+ GB of it). In addition, my computer's remaining hard drive space was about the same (certainly less than 1 GB difference) as it was before.

The video's name was "name-0.mov" (changing the actual name to keep it simple), which may or may not be correct. I did notice that none of the other videos in the other events had a -0 suffix, so I tried changing it by deleting the suffix. When I re-opened iMovie, I found that the warning triangles had disappeared from the timeline; however, the viewing window still displayed the message and refused to play the video. In addition, the little square that usually displays the FPS rate now said "0" instead of the usual "24".

So, here's my question: What's going on, and how can I fix it?

Here are a few other details (which might be irrelevant, but whatever):

• I looked at the file path on the video clips (by hovering over them) and it is the same as the source video's location and name.
• When the video has the -0 ending, the red playhead moves smoothly. When it is removed, the playhead moves choppily (think 1 FPS) and iMovie immediately uses 80%+ of my CPU.
• The Trash is empty on my computer, probably becasue I've emptied it several times (after confirming that the clips weren't there).
• I selected "Show all clips" for the event. The video isn't there at all--it's not just rejected or something.
• I cannot open the source video in QuickTime; its icon also suggests that it's corrupted or messed up somehow.
• The source video is playable in the "iMovie Temporary Items" folder. This video is 9.89 GB; the one in the Events folder is 8.83 GB. Not sure if this means anything.

I'd be really grateful if anyone could show me how to fix this problem. I do have more copies of the source video, so if I just need need to replace the current video file with another one and change something to make it work, that'd be great.

Please let me know if you have any ideas, and thank you in advance for your time.