Trouble combinging video projects

I created numerous video projects using imovie and now I want to combine them into one. However, one of the videos I want to use shows up on my projects page but doesn't show up as an option when I click on create movie. Anyone else have this issue? How can I fix it?

In addition, when I click on Import Project it doesn't tell me where it is going to import it. So, where does imovie import projects to?