Nedarim 77: Did You Nullify Your Vows before Candle-lighting?

Revoking and annulling vows on Shabbat - the latter, specifically for things needed that same Shabbat. Plus, revoking vows at night - but why does this need to be stated? What happens when the vow is made on Shabbat? Wrapping up these issues, or almost. Also, can judges nullify a vow while standing? Rabban Gamliel dismounted his donkey to adjudicate a case... Does that answer the case? Plus, the sin in vowing, and the source for it.