There's no way an out of work computer engineer could not have heard of bitcoin until so recently unless he was living in a cave. The hype of bitcoin was quite large and pretty much anyone computer literate would have heard of it, especially a guy who's name is Satoshi Nakamoto. As to his claim of thinking he was talking about "bitcom" not bitcoin, well according to the Newsweek article, Dorian was first informed of bitcoin through email, which means he likely could not have confused that word with anything else. Furthermore, he claimed he was told by his own son about it before he talked to the AP reporter where the confusion arose. Which means he has at least two clear-cut occasions where he would have been corrected beforehand. Finally, his claim of the "accusation" hurting his job prospects are quite silly, since he's been out of work for more than a decade. The argument makes very little sense, nor does it seem plausible being accused of creating bitcoin at all would hurt your job prospects. All in all, it's clear that Dorian is not being honest, and certainly you cannot trust his words at all.
Finally, if you believe he is the creator of bitcoin, then you must also realize he is a very intelligent man and should very easily write coherent English that could pass for a younger person, and then mask it in person when accused. On the other hand, he probably can't, no matter how smart he is, completely defeat logical analysis when is directly fingered. Plus, it's pretty rare to be this vehement in your denials unless there actually is some truth to the accusation (see Lance Armstrong, Roger Clemens, etc.). So I still see Dorian as being very likely being the guy, and this article doesn't do a particularly convincing job dissuade me otherwise.