Imovie wont let me create a project.

I'm trying to create a video for my youtube channel, and when I try to create a new project it doesnt work. Here is the steps I go through.

1) File > New Movie

2) I choose my theme

3) I name my movie

4) I try to choose an event but it doesnt let me click Imovie library

then when I click enter it says Operation cannot be complete, No other information is avalible on this problem. I am so frustrated! What should I do? Thank you so much for reading this!