March 7, 1982

Members of the Organization of Petroleum Exporting Countries have apparently reached agreement on a last-ditch effort to prop up sagging oil prices and will hold a special meeting in two weeks to ratify it. In informal talks in Doha, Qatar, over the last two days, the group, which will meet again in Vienna on March 19, decided to cut production limits by more than a million barrels a day to stop the fall in open-market prices. ''Any observers who are expecting that prices will go down will find they have made a complete mistake,'' said Mana Said al-Oteiba, Oil Minister of the United Arab Emirates and the current president of the 13-nation OPEC group. Informal Talks by Arab Producers The consultations took place in Doha during a meeting of the Organization of Arab Oil Exporting Countries. This organization is made up of the seven Arab members of OPEC - Algeria, Iraq, Kuwait, Libya, Qatar, Saudi Arabia and United Arab Emirates - plus Bahrain and Syria, which do not belong to OPEC.

Victory in El Salvador, from the Reagan Administration's point of view, will take a lot more fighting there and a lot of explaining in Washington. Last week, despite stepped-up activity on both fronts, Reagan officials were claiming no big advances. One Presidential aide acknowledged ''the success of the El Salvador insurgents in the past couple of months.'' President Reagan was told that the guerrillas might succeed in disrupting March 28 elections, a crucial element of Administration strategy to gain legitimacy for a centrist government. Without explanation, the Salvadoran Army cut short a major offensive against guerrilla strongholds 20 miles from the capital.

Secretary of State Alexander M. Haig Jr. and Foreign Minister Jorge Castaneda of Mexico met in New York yesterday to discuss the situation in Central America. But they disagreed over the issue of Nicaraguan arms shipments to leftist insurgents in El Salvador. After the two-and-a-half-hour meeting, Mr. Haig told reporters that a failure to deal with the Nicaraguan concern was the principal weakness in the peace plan advanced last month by President Jose Lopez Portillo of Mexico. Mr. Castaneda described the current arms flow from Nicaragua to El Salvador as ''fairly small and unimportant.'' Halting it, he said, depends on United States concessions, among them a less belligerent attitude toward Nicaragua.

TRENTON THE state's Democrats were caught overreaching last week when a three-judge panel in Federal District Court here ruled, 2 to 1, that the Congressional districts designed by the last Legislature and signed into law by former Gov. Brendan T. Byrne were unconstitutional. In their zeal to gerrymander the Republicans almost out of existence, the Democrats, in the eyes of the court majority, did not do as well as they could have to design districts with nearly equal populations. Under the one-man, one-vote doctrine, the districts are supposed to contain the same number of residents. Period. Everyone recognizes that absolute equality is impossible, but that is the goal, and any deviation from that goal must be justified. Those in charge of drawing the maps - in this case, it was the Democrats in the Legislature - must prove that they made a ''good faith'' effort to include the same number of people in each district without going to the extreme of drawing a line through someone's bedroom.

IVORYTON THE wooden seats were a symbol - certainly of discomfort, and possibly of failure. But now, the director of the venerable Ivoryton Playhouse, in its heyday billed as Connecticut's ''first and oldest'' summer stock theater, says that the old chairs will be torn out and replaced by a new set of movie-theater type seats, their cushions upholstered in gray and blue. The mood in the theater now is vastly different than it has been. With its roof leaking, its shingles falling off and the paint on the letters of its name flaking, the playhouse was sold in 1973 by its founder, Milton Stiefel, who had owned and run it since 1930. Several men tried to manage the theater in Mr. Stiefel's style, with big names and Broadway shows, but they failed.