One project won't open for either user, another will open for one user only

Question

My wife and I are new iMovie users. I have imported three projects (#1-3) from our camera, she has imported two projects (#4 & #5) - all to a shared folder. The first project I imported (#1) cannot be opened by either of us. In addition, my wife cannot open the second project that I imported (#2). We get the following error: "The project could not be opened, because the disk is full, the folder is locked, or the folder permission are incorrect." We can both open projects #3-5.
I have checked the permissions settings on all 5 projects. All are same, Read and Write priveleges for both of us. Anybody seen this before? Am I missing something?
G5   Mac OS X (10.4.6)  

Answer 1

1. You said the projects were all saved "to a shared folder." Do you mean THE Shared folder? Your Mac's Users folder should list two Users, plus a folder named "Shared". Is that the folder you mean?
2. The trouble is that an iMovie project isn't actually a file. It's a special kind of folder called a package, which contains other files and folders. (To look inside the package, Control-Click on the package icon and choose "Show Package Contents" from the popUp menu.)
3. When YOU are the user and you create a new iMovie project, the package and everything it contains is configured with you as the owner. You are the designated owner of all the items that comprise the project. No one else can Write to the project.
4. To change that, you have to change the project package into a normal Finder folder, adjust its permissions and the permissions of all the contents of that folder, then change it back into an iMovie package.
Here's how:
In the Finder, choose Finder > Preferences. Click Advanced and turn ON "Show all file extensions".
The name of your iMovie project "My Sample Project" is now displayed as "My Sample Project.iMovieProject" in the Finder.
Remove ".iMovieProject" from the project name, removing the period. When the Finder asks, say OK.
The project package has now turned into a folder. Select the folder and choose Get Info.
Set Others permissions to "Read & Write". Then click "Apply to enclosed items". When the Finder asks, say OK.
Select the folder name again and add the extension ".iMovieProject" to the name. The folder will change back to an iMovie package.
The package will now allow anyone to Read and Write to the project.
Karl
PS: This solution isn't very handy, obviously, but it does the job. A better solution is to buy an external hard drive, and configure it to Ignore permissions. (In the Get Info window for the disk.) That lets both users save projects to the drive without permission issues.