[Plugin: Cache Manifest for WordPress Themes] fetch failed (-1)

I can’t get this to work, and I get this message in Chrome:

Creating Application Cache with manifest http://www.riisdesign.no/wp-content/themes/riisdesign-business/cache.manifest
Application Cache Checking event
Application Cache Error event: Manifest fetch failed (-1) http://www.riisdesign.no/wp-content/themes/riisdesign-business/cache.manifest

The link to my website is: http://riisdesign.no/

Any suggestions?

http://ww.wp.xz.cn/extend/plugins/cache-manifest-for-wordpress-themes/