Here is Yesins original article (in Russian):
http://vpk-news.ru/articles/8838
Yesin claims China is producing fissionable material at a place called Koko Nor. However, China closed Koko Nor in 1987 and moved their nuke weapons design and fabrication to Mianyang.
Karber could have seen those errors and amended his analysis. Karber should also know that the Epoch Times is run by the Falun Gong.
The Epoch Times has the Alice in Wonderland position of being virulently anti Communist yet pro extreme Socialist, because, as you point out, they are a publicity organ of the Falun Gong. They would take an opportunity to demonize the Communists, if one presented it's self.
However, the new China is very aware of the power of publicity and perception, and would conceal activities that would create a disturbing perception of China in the international community.