What is the test for "willfulness" in a charge of aiding and abetting a crime?

deed, immediately before the instruction on willfulness, the jury was informed that "[i]n order to aid or abet another to commit a crime, it is necessary that the defendant willfully and knowingly associate herself in some way with the crime and that she or he willfully and knowingly seek by some act to help make the crime succeed." Tr. 5035 (emphasis added). Immediately after the challenged language, the jury was instructed that the "mere presence of a defendant where a crime is being committed, even coupled with knowledge by the defendant that a crime is being committed, or the mere acquiescence by a defendant in the criminal conduct of others, even with guilty knowledge, is not sufficient to establish aiding and abetting." Tr. 5036. Cf. United States v. Elfgeeh, 515 F.3d 100, 134-35 (2d Cir.2008) (finding it "highly unlikely" that jury relied on erroneous sentence that was immediately preceded and followed by correct statements of the charge). An aider and abettor, the district court said, must "know that the crime is being committed and act in a way which is intended to bring about [its] success." (emphasis added).