Hmm. I'm not sure what to make of that analysis, because it seems to me that the claim is that Obama can't carry poor white voters - which is what Appalachia largely is - not that he can't carry white voters. The PeeDee's article is a clarification of the demographic breakdown, but it doesn't add any additional insight, and it certainly doesn't resolve any questions as to how Senator Obama can reach those voters from Vinton County, Ohio, to Rabun County, GA.
Actually, it does do one thing: it provides a geographic overlay to the issue. Go PeeDee... you get a gold star.