A Bosnian Serb general broke a promise to meet Monday with NATO commanders and Muslim and Croat generals, who negotiated without him on a U.S. warship in the Adriatic Sea. Angry NATO officials said the Serbs would have to explain why they were violating the Bosnia peace accord. The no-show proved again how hard it is to get Bosnian Serbs to comply with a peace accord they did not want; they were represented at peace talks by President Slobodan Milosevic of Serbia. Gen. Zdravko Tolimir, deputy commander of the Bosnian Serb army, did not show up at Sarajevo airport by noon, when talks were supposed to have started.