What does it mean when I see an error message that prompts that content is protected using digital rights management?
This error message is displayed when you attempt to import audio or video that has been protected with digital rights management (DRM). DRM is a technology that lets content authors and publishers, such as record companies and movie studios, control how their digital music and video files are used and distributed. Protected digital media files cannot be imported into Windows Movie Maker.
Note: This information provided by Microsoft.