Supporting post thumbnail in theme crashes edit and add page

HII folks,

i had a complex situation here and i need some guidance please,

i have created a new theme using roots starter theme, and created some custom posts, taxonomies and meta boxes. all that went fine until i found that add post page and edit post page is not working.

and that error appears in console

Failed to load resource: net::ERR_INCOMPLETE_CHUNKED_ENCODING[]=hove…ck,word-count,editor,quicktags,wplink,wp-fullscreen,media-upload&ver=3.9.2

i tried removing all the custom post types and all other function i have created but nothing fixes the problem except removing that line

add_theme_support( ‘post-thumbnails’ );

the live website is here

Any help is appreciated,