iMovie communication error with Youtube

I just got an iPhone 4 and have been playing around with video. I've been able to upload videos through my iMovie (on my laptop) fine a few times, but not I'm getting a communication error message. The categories part will say "Downloading..." but it will never show the categories, and if I try to move forward, I get an error message saying "An error occurred during communication with the server ("Could not connect to the server."). Please make sure you are connected to the internet (I am), and then try again."

I've been trying for the past few days. I know it's not a Youtube error 'cause I've managed to upload videos to Youtube in other ways (e.g. Pixelpipe via iPhone). Does anyone have any suggestions on how to fix this?

Thanks.