What's wrong with DBMS_OUTPUT.PUT_LINE buffer overflow?

I want to follow the progress within a PL/SQL block. A problem is that Oracle doesn't show the results directly (afterwards) and I get the following error:
ORA-20000: ORU-10027: buffer overflow, limit of 2000 bytes ORA-06512 Can somebody tell me how tot manage progress within PL/SQL?

set serveroutput on

LOOP
....
....

       my_counter := my_counter + 1;
      IF ins_teller MOD 10000 = 0
      THEN SELECT TO_CHAR(SYSDATE,'DD-MM-YYYY HH24:MI:SS') INTO t_sysdate
FROM DUAL;
           dbms_output.put_line('processed  ' || my_counter || '  ' ||
t_sysdate);
      END IF;