I am not able to open one particular iMovie project - help!

Question

I spent 18 hours editing a video, then closed imovie so that I can continue the next morning and wanted some memory management to happen. Now when I restart iMovie I can see the project in the list but open project button at the top is grayed out and double clicking puts the cursor on the name as if I want to rename it. Reading some other forums, I have tried deleted some files so that iMovie recalculates/adds those files to the iMovie project but that didnt help as well. I am still able to see the event in the bottom half of the screen with the rejected/chosen parts intact but cant load the project on the timeline.
Previously while loading I had chosen to copy the video files from original location to iMovie project and then move the original files to a USB drive and have confirmed that the mov files iMovie created for the project is there.

Answer 1

The individual file has become corrupted somehow.
Happens often to users who work across a network, opening or saving a Photoshop image file to a server.
You're going to have to resort to your backup.
This is the boilerplate text often used in connection to saving to a network (please NOTE the part where it explains that normally, it does work, but that it is impossible to troubleshoot someone else's network remotely, and that's why it's not supported by Adobe):
If you are opening files over a network or saving them to a network server, please cease and desist immediately in the event you are currently experiencing problems with one or more files. Working across a network is not supported.
See: 
http://kb2.adobe.com/cps/406/kb406793.html
  Copy the CLOSED file from your server to your local hard disk, work on it, save it again to your local hard disk, close it, and copy the closed file back to the server.
     Of course, the fact that Adobe does not support working across a network does not necessarily mean it won't work.   It should.
    Adobe's position is that there are too many variables in a network environment for them to guarantee that everything will work correctly in every network, especially given the fact that if something does not work properly, it's probably the network's fault, and Adobe has no way of troubleshooting your network.
  If you can't work locally, you are on your own, and if something happens, you're on your own. If you must work from a server, make sure your network administrator is a competent professional.
When problems arise, a lot of valuable work can be lost.