I'm using iMovie for the first time, having played with it not knowing what I'm up to previously.

I have video I want to edit on my Mackbook Pro hard drive, but iMovie keeps flashing up an error message saying it can't connect to my network hard drive (WD My Book World), which is correct, the drive is switched off unless I want to use it.

How can I stop iMovie looking for the switched off drive and reporting back with the error message?