Continuing problems with the Northern Virginia Association of Realtors' new computerized multiple-listing service has spurred one frustrated real estate broker to file a class-action suit against the association and hundreds of real estate agents and brokers to complain about the system to their association.

In his lawsuit, filed this week in Fairfax Circuit Court, broker Lawrence Doff said the problems with the new multiple-listing service (MLS) have hurt his business and that he has been unable to use the new system with his office's equipment.

Doff, president of his own realty firm, Real Estate Professionals Realty Inc. of Annandale, is seeking $5,429 in damages for what he said was "ineffective service" from the new system. He estimated that other agents may be entitled to up to $500,000 in damages.

Doff and two dozen other frustrated real estate agents, calling themselves Realtors for an Effective MLS, have been conducting a survey of NVAR members. They said that more than 800 members have signed a petition complaining about the system. "You walk into any real estate office and ask any agent about the system and they'll tell you it stinks," said Bob Terpstra, a Re/Max real estate agent in Great Falls who signed the petition.

The source of the Realtors' frustration is a $15 million MLS system installed July 1 by Dator Corp. of Greenwich, Conn., for use by members of NVAR and four smaller boards of Realtors in Northern Virginia. The system is supposed to give its 17,000 users -- including real estate agents, appraisers and lenders -- easier access to information on the thousands of properties for sale in Northern Virginia. But it has been plagued with problems from the beginning.

About 200 angry real estate agents demonstrated outside the association's Merrifield office in mid-July. Since then, agents have poured out their frustrations via the MLS system's new computerized bulletin board, calling the new system a "shabby bill of goods," "third-rate at best" and "junk."

Gayl Warman, NVAR's new president, declined to comment on the lawsuit.