Finally got through to the license server...
So, we would assume that a Larry Peterson would either be named Larry, Lawrence, or have a middle initial of L and be somewhere around Denver. You'd also guess that their license status would be active if they're a big cheese in some prominent accounting firm.
Guess what? There are no Larrys or Lawrences, period, for either Peterson or Petersen. There's only one active guy with a middle initial of L around Denver, and that's up in Loveland. I'm sure people do commute from Loveland, but it makes it less likely.
So, add that to the rather fishy-sounding group that he supposedly spoke to and the mysteriously nebulous details, and I think I can put this one to rest as a work of flamebait fiction - possibly, as other have pointed out, by someone we already know.