Other mistake: Jack follows J. Edison Nash to a wine warehouse and watches as Nash punches numbers on a keypad in order to gain entrance to a private room. Nash punches the 6 and a beep is heard. He then punches the 8 and another beep is heard. During a close-up of Jack, four more beeps are heard, for a total of six. Jack says the number out loud - 862, which is only three digits.
Other mistake: While Mark is being roasted, a guy comes up on stage and starts causing trouble. When the lights go out for a brief second then come back on, the heckler is seen facing the audience with his back facing Mark and the comedians. Since his back is to everyone sitting at the table with Mark, they should have already seen the knife plunged deep into his back, but, no one reacts until the heckler turns to his side and then the audience, Mark and the comedians react with shock.