Did Parley P. Pratt make false prophecies in his 1838 Mormonism Unveiled?

I have come across a few sources, both in print and online, that have claimed that Parley Parker Pratt (1807-1857) was guilty of stating a number of (false) prophecies in his 1838 volume, Mormonism Unveiled, a response to L.R. Sunderland, an early critic of the LDS Church.

The FairMormon wiki has a good page refuting this argument here.