The official in charge of the District of Columbia's three-month-old computerized financial management system acknowledged yesterday that the system has some troublesome bugs -- but insisted they are being eradicated.

Colin F. S. Walters, assistant city administrator for financial management, made the statement to reporters after a meeting that included Mayor Marion Barry and Sen. Thomas F. Eagleton (D-Mo.), chairman of the Senate subcommittee that oversees D.C. legislation.

In addition to keeping the city's books, the new system is designed to provide an automated way for the District to pay its bills and write its payroll checks.

Before the system went into operation Oct. 1, Walters predicted there would be a rough initiation period.

Walters said this has come true, with some firms that sold goods or rent buildings to the city being paid late, and some employes not receiving paychecks on time. In one instance, he said, 17 police officers went payless, and the city had to take emergency steps to provide them with checks.

In another instance, he said, the computer spat out checks that lacked the dollars-and-cents amount on their faces.

"Once such things are solved, they're solved," Walters said. We'll be in a shakedown period for a whole year, maybe longer."

Using the new system, the city now sends out checks to suppliers within seven days after personnel of city departments enter the necessary information in a computer terminal -- a vast improvement, Walters said, over the previous timetable.