FCP 6 files going offline

Greetings!
I'm using FCP 6.0.6 on a mac book pro, OS 10.6.8 w/ one terra hard drive. I am having a heck of a time with my logged and captured footage going offline. I try to reconnect but the files I'm looking for don't come up for me to choose, sometimes they do, but the files never connect.
Is there a solution? I am in rural Alaska working with a school district to create documentaries with students---any help would be appreciated.
Thank you,
Di