Install Theme which clone from "Elegantblue" theme don't work

I’used EasyBlog 5 and want to clone themes of EB. I cloned elegantblue theme, but i can’t install by install theme feature in backend with error
Fatal error: Class 'Foundry' not found in /DATA/www/demo/joomla-templates/jsn_pixel/j30/pro/administrator/components/com_easyblog/models/themes.php on line 71
Please help me this case