Not sure if this qualifies as an error, per se, but the repetition of the deal with the four-pieced statue from the "History" section again in the "Current Situation" was a bit... repetitive. Like, word for word.
the dragon priests believed the weapon to be too dangerous to be used except in extreme emergencies. Opening the crypt required a special key: a statuette split into four pieces, one for each direction ruled by the dragon emperor.
p. 6, followed on page 7 by
According to ancient writings, the statuette has been split into four pieces – one for each direction ruled by Eledain – which must be assembled in order to open the gate
Also, just as a personal note: I'd make the key initially be a single statue that was broken into four pieces during Eledain's sons' feud over rulership. (The priests basically saying "None of you is fit for the sword unless you cooperate to unseal it.")