Problem with JustWrite and Embeed wordpress function

Hi and a lot of thanks for read my post, i have installed the Justwrite theme and everything its so cool until i try to embeed a video of Youtube.

since WordPress 4.0 all users can embeed things of a lot of sites (Youtube videos, Soundcloud URLS, Tweets, Instagram Post etc) just putting the direct object code (example: a direct link of a Youtube video) and wordpress automaticaly embeed the video.

I can’t embeed anything on this way and im very sad cause i need to paste the original embeed code and its so difficult and slow.

¿how can i solve this situation? I really like the theme and i cant find nothing anywhere.

Thanks a lot