Errors and crashing: "No plugin known to handle file.."

[pagesrichie]

While installing this a new error comes up:

error: No plugin known to handle file 'themes/default/assets/fonts/icons.eot'. If you want this file to be a static asset, use addAssets instead of addFiles; eg, api.addAssets('themes/default/assets/fonts/icons.eot', 'client').
   error: No plugin known to handle file 'themes/default/assets/fonts/icons.svg'. If you want this file to be a static asset, use addAssets instead of addFiles; eg, api.addAssets('themes/default/assets/fonts/icons.svg', 'client').
   error: No plugin known to handle file 'themes/default/assets/fonts/icons.ttf'. If you want this file to be a static asset, use addAssets instead of addFiles; eg, api.addAssets('themes/default/assets/fonts/icons.ttf', 'client').
   error: No plugin known to handle file 'themes/default/assets/fonts/icons.woff'. If you want this file to be a static asset, use addAssets instead of addFiles; eg, api.addAssets('themes/default/assets/fonts/icons.woff', 'client').
   error: No plugin known to handle file 'themes/default/assets/fonts/icons.woff2'. If you want this file to be a static asset, use addAssets instead of addFiles; eg, api.addAssets('themes/default/assets/fonts/icons.woff2', 'client').
   error: No plugin known to handle file 'themes/default/assets/images/flags.png'. If you want this file to be a static asset, use addAssets instead of addFiles; eg, api.addAssets('themes/default/assets/images/flags.png', 'client').

also seems like icons don't work at all