One point of clarification that I didn't convey so clearly in the recording: The first version of Rav Nahman bar Yitzhaq holds that the only time that a person who forgets Yaaleh Veyavo has to repeat the Amidah is when he BOTH took three steps back AND doesn't add supplications at the end of his prayer. If he EITHER hasn't stepped back OR he has stepped back but typically adds supplications, then he is still considered involved in the prayer and can go back and correct it without starting over. The second version holds that if the person took three steps back he must start over no matter what; in fact, even if he hasn't taken three steps back yet, if he doesn't generally append supplications to the end of his Amida, then as soon as he is finished with it and is READY to step back, he can no longer salvage/correct his prayer.
Another point: In Havinenu, the phrase "Ve-hatoim al daatkha yishapetu" can also be read "al daatkha yishpotu" depending on how it is interpreted. If it means "those who err should be judged by Your wisdom", then the former is correct, but it seems that Rashi's preferred interpretation - that it means "judges who err should instead judge according to Your wisdom" - fits best with the latter.