SQL> DECLARE
  2     v_test VARCHAR2(1);
  3  BEGIN
  4     v_test := 'bananas';
  5  END;
  6  /
DECLARE
*
ERROR at line 1:
ORA-06502: PL/SQL: numeric or value error: character string buffer too small
ORA-06512: at line 4

SQL> CREATE TABLE bananas (name VARCHAR2(1));

Table created.

SQL> INSERT INTO bananas (name) VALUES ('One banana two banana');
INSERT INTO bananas (name) VALUES ('One banana two banana')
                                   *
ERROR at line 1:
ORA-01401: inserted value too large for column

FOR indx IN 1 .. l_c1_main.COUNT 
LOOP
rec_count := indx;

dbms_output.put_line('----before1----');
r_data_rec.firstName := l_c1_main(indx).FIRST_NAME;
dbms_output.put_line('----before2----');
r_data_rec.lastName := l_c1_main(indx).LAST_NAME;
dbms_output.put_line('----before3----');
r_data_rec.email := l_c1_main(indx).EMAIL;
...... 
END LOOP;