NEW YORK -- FleetBoston Financial Corp. has decided to pull the plug on Robertson Stephens, its investment-banking division that in its heyday took some of the country's best-known dot-coms public. The decision comes after weeks of often-tense negotiations between Fleet and a management-led buyout team at Robertson. Despite an announcement in late June by the two sides that "an agreement to work together" had been reached, the pair failed to reach an deal. "I am sad to announce that the deal won't move forward and that Fleet has decided to shut down the firm," Robertson Chief Executive John Conlin...