And they were pretty basic mistakes:

AMID much publicity last year, the National Geographic Society announced that a lost 3rd-century religious text had been found, the Gospel of Judas Iscariot. The shocker: Judas didn’t betray Jesus. Instead, Jesus asked Judas, his most trusted and beloved disciple, to hand him over to be killed. Judas’s reward? Ascent to heaven and exaltation above the other disciples.
It was a great story. Unfortunately, after re-translating the society’s transcription of the Coptic text, I have found that the actual meaning is vastly different. While National Geographic’s translation supported the provocative interpretation of Judas as a hero, a more careful reading makes clear that Judas is not only no hero, he is a demon.
Several of the translation choices made by the society’s scholars fall well outside the commonly accepted practices in the field. For example, in one instance the National Geographic transcription refers to Judas as a “daimon,” which the society’s experts have translated as “spirit.” Actually, the universally accepted word for “spirit” is “pneuma ” – in Gnostic literature “daimon” is always taken to mean “demon.”
Likewise, Judas is not set apart “for” the holy generation, as the National Geographic translation says, he is separated “from” it. He does not receive the mysteries of the kingdom because “it is possible for him to go there.” He receives them because Jesus tells him that he can’t go there, and Jesus doesn’t want Judas to betray him out of ignorance. Jesus wants him informed, so that the demonic Judas can suffer all that he deserves.

Those are embarrassingly obvious errors.
(via)