Problem Solved--> Solution:Yell at software for one hour, keep closing and opening the project, and on the 11th try it'll work.
Well, glad you found a short-term solution anyway -- but I'm sure you'd like to get to the bottom of it.
If so, tell us more about your camcorder and your computer. What type of camcorder is your video coming from and what are your computer hardware specs and operating system?
Yes, I like yelling at the software. I also will start looking at computer Web sites, and spec'ing new boxes. My computer sees me doing this and then starts to behave better!
Along with Steve's questions, pay special attention to the I/O sub-system, i.e. your computer's HHD's (Hard Disc Drives). Explaining exactly what you have, how they are connected, i.e. 3x 250GB 7200RPM SATA II internals, 1x 1TB Maxtor 7200RPM FireWire-800 external, etc.. Then tell us how you are using these HDD's, i.e. C:\ OS and programs w/ Windows Page File, D:\ media only, E:\ Projects and Scratch Disks, F:\ Captured files, etc.
I also recommend that one does a regime of Saves, Save_As and Save_As_a_Copy, while doing an involved edit. Obviously, we all know what Save (Ctrl-s) does - it overwrites the existing .PREL (Project file), in the location where you originally placed it. This will also trigger the AutoSave function, if not disabled.
Next we have the two "Save_As" functions. The both have a purpose, and are very slightly different. Save_As will allow you to NOT overwrite your original Project file, if you change the name. I like to numerically increment these, i.e. [Project Name]_01, _02, etc. What sets it apart from its cousin, Save_As_a_Copy, is that it will then let you keep working on your new [Project Name]_01 file. Your original is now NOT in PrE. The new, incremented version is. Your original is safe and will remain untouched. I will use this function, as I edit. Before a big change, or a series of experiments, I'll do the Save_As, increment by 1, and then do the work. If it looks good, I immediately do a Save_As_a_Copy. I place this in a separate folder, and make sure that "Copy" is in the new file name. The big difference is that I am NOT now working on that file, it is just saved, and is not loaded into PrE. At the end of the day, I always do a Save_As_a_Copy, plus my normal Save. Putting my Save_As_a_Copy files into another folder helps me keep track of all of the versions. It's easy to do and I'm seldom too far from a recently saved version someplace.
This gives me a "bread crumb" trail to some "last known good" versions of my Project, plus I have the AutoSaves too. While editing, I'll hit Ctrl-s (Save) often. This comes from the old days, when I used Pinnacle. You never did more than two things, without hitting Ctrl-s. I probably do this more often, than is needed, but it is such a habit, and does not hurt, so long as I have my Save_As and Save_As_a_Copy files.
When one encounters any sort of Media Offline situation, regardless of the cause, the first thing that I do is a Save_As, BEFORE I do anything else. This keeps my original Project file untouched, and allows me to explore the Media Offline issue without touching that original. You never know when you might need it exactly as it was. Because I did the Save_As, all changes that I make are now in the new file, because it's now the one loaded into PrE.