The upload failed due to an unknown error

Hello All,
I have been using Windows Movie Maker on my Windows Vista machine. But today when I tried to upload a movie, I got an error message that there was an unknown error message.
Since the error message is not that specific about what could be the issue, I am posting it here.
My Movie.wmv (2.24M)
The upload failed due to an unknown error.
What do I do for this error message?
