1 individual project locking up

I have a 4tb hard drive with 5 different network shows that my editor put together. One of the episodes opens up, but as soon as I move the mouse, the rainbow wheel of death makes an appearance and never leaves. All the other projects in all the other libraries work just fine, but this one seems to be stuck. Any suggestions? I'm checking with him to see if he kept the backups. Also, I don't think I need to reinstall FCX because all other projects are working fine. Thanks. DL