According to the product's official website, the developers are working to release a new version of Movie Maker, that will definitely be compatible with Windows 8. This is the only information that is released until this point. Regarding the error that you encounter, this might be present due to the incompatibility of the application with the OS that you are using. Until this point, there is nothing that you can do, beside the fact to wait for the new release. I suggest that you regularly visit the site mentioned above to find out when a release date is announced.