In the excerpt from Wilson's translation quoted below, notice that where Erasmus uses maleficium in the original, Wilson translates this as "Witch". No big surprise there, perhaps. But then again, perhaps not.
You see, if we read on, the original and the translation taken together clearly demonstrate that even when the word "Witch" is being used as a direct gloss of maleficium, this does not necessarily refer to one who uses magic to cause harm. (Exclamation point!) Indeed, Erasmus has done us the favor us telling us explicitly, at least in his opinion (and when it comes to Latin Erasmus is someone whose opinions can be taken rather seriously), what sort of magical workers maleficium does refer to: "fortunetellers [sortilegos], enchanters [incantatores], and magicians [magos]."
Link to Wilson's translation: http://www.fordham.edu/halsall/mod/1509erasmus-folly.asp
The following is from near the end, specifically the section "Folly Attends a Theological Dispute":
And now, as many as were present admired the man's wit, and consequently submitted to his decision of the question. Nor came it into any of their heads that that law concerned only fortunetellers [sortilegos], enchanters [incantatores], and magicians [magos], whom the Hebrews call in their tongue "Mecaschephim," witches or sorcerers.