TALKS between officials backed by Haiti's Army and ousted President Jean-Bertrand Aristide broke up last weekend without agreement. But according to Haitian observers, both sides in the talks in Cartagena, Colombia, made major concessions that bode well for a future accord.The Army's parliamentary allies accepted Mr. Aristide's return in principle, while Aristide conceded that he and parliament would jointly choose a new prime minister, these observers say. The stumbling block was Aristide's call for an explicit reference to his future reinstatement in the final statement, while the parliamentarians insisted on nothing more precise than a reference to a constitutional clause that presidential terms last five years, along with a pledge to "return to the constitutional order." "We couldn't be more specific because there would have been soldiers shooting at the airport when we came back to Port-au-Prince," one of the legislators said, alluding to hard-line Army factions opposed to Aristide's return under any circumstances. The details of his return "should be debated in a big, national conference... that brings all sectors together," suggested another lawmaker, House Speaker Duly Brutus. The proposal drew swift criticism from Port-au-Prince Mayor Evans Paul, who was arrested and beaten by soldiers in early October and, like many Aristide supporters, is now in hiding. "Why are we talking about a national conference to decide Aristide's return when we know it is just a handful of Aristide's political foes who will be able to take part," Mr. Paul said in a taped message delivered to radio stations. The legislators indicated Aristide's reinstatement would probably be implemented in stages. First would come the formal agreement on the principle of his return, then the choice of prime minister, then approval and installation of a new Cabinet, and finally - the most delicate phase - the return of Aristide himself. "Staggering it like that makes it more palatable to the military," says a businessman who claims some familiarity with the 7,000 member Haitian Army. "They may agree in order to get the OAS to lift the embargo, but a lot of them will be hoping that something happens to stop the final stage materializing." From the outset the Army has tried to drive a wedge between Aristide and the 34-nation Organizaton of American States, which has worked closely with the ousted president, accepting his authority and legitimacy. But OAS diplomats are voicing concerns about the effect on the poor of the group's embargo on essentials, and Army allies are playing to those fears. "It is President Aristide's responsibility if people die in this country now because they cannot get to hospital," Senate Speaker Dejean Belizaire said this week, alluding to the collapse of public transportation caused by gasoline and diesel fuel shortages. No fuel has been sold in gas stations for the last two weeks. Small amounts of black-market gas and diesel are available at five times the official price. The power and telephone companies are both expected to stop work within the next 10 days. According to a banker, prices have risen 25 percent in the last month, but many food staples have jumped more. When there is no electricity for pumping stations, clean drinking water supplies will also end, raising the likelihood of disease, health officials say. Yet so far there is no sign of unrest among the shantytown dwellers or the peasantry, where Aristide's popularity is undiminished and the embargo is accepted stoically to bring his return. The embargo, together with a continuing military manhunt against suspected pro-Aristide activists, has set off an unprecedented exodus of Haitians trying to sail to Florida. Prime Minister Jean-Jacques Honorat of the Army-backed interim government had made doom-laden forecasts about such a surge. The United States Navy and Coast Guard have since mounted a massive interception that has stopped 5,000 Haitians. But the exodus "does not necessarily work in Mr. Honorat's favor," a Western diplomat says. "It could just make the United States push the decisionmakers to accept Aristide's return faster."