[Plugin: WordPress Download Manager] Change embed code

Can I change the embed code of a file? When I try to do this and press enter, the entire page become blank and I’ve to return to previous page, so it don’t run. How can I do? I have to link a file in the header.php with a do_shortcode, it runs but I want the file change frequently with the same link, so I want to change the file id in the admin page instead of change the header.php. Thanks

http://ww.wp.xz.cn/extend/plugins/download-manager/