A 37-year-old Hyde Park man pleaded not guilty Monday to charges in a fatal shooting Dec. 14 in Dorchester, authorities said. Andrew Robertson was arrested Friday on a warrant charging him with the murder of Romeo McCubbin, 25, of Boston, police said. Police officers, responding to an emergency call, found McCubbin on Havelock Street at 1:45 a.m. on Dec. 14. He was pronounced dead at the scene, police said. Robertson was arraigned in Dorchester District Court.Martin Finucane can be reached at firstname.lastname@example.org.