So what does his errors on the Nephilim have to do with the Sumerians? Or Ur of the Chaldees, Babylonian. Is he wrong on everything he's ever research or written about? That would be pretty incredible, wouldn't it? The guy writes 10 books and doesn't get anything right. Hahaha.
Heiser points out that Sitchin simply doesn't know whereof he speaks, and shows how Sitchin fabricates things -- including meanings to words which were defined by the ancients themselves. Sitchin's 3600 year orbiting planet doesn't exist, and as at least one reviewer noted, the orbital characteristics Sitchin gives for it in "The Twelfth Planet" (which is after all the first of the books) are impossible.