ORA-06502: PL/SQL: numeric or value error: character string buffer too small

Hi, I have this error when i run this query :

ERROR:

ORA-06502: PL/SQL: numeric or value error: character string buffer too small

ORA-06512: at "SYSADM.FIND_VALUE_CASE", line 13

select             A.Case_id

    || ';' ||    B.DESCR

    || ';' ||    A.CASE_TYPE

    || ';' ||   A.ROW_ADDED_DTTM

    || ';' ||   A.RC_STATUS

    || ';' ||   A.RC_CATEGORY

    || ';' ||   (select X2.RC_DESCR_SS from ps_RC_CATEGORY_TBL X2,PS_RC_CASE Y2

                                    where setid=A.BUSINESS_UNIT

                              AND    X2.RC_CATEGORY=Y2.RC_CATEGORY

                              AND    Y2.RC_CATEGORY=A.RC_CATEGORY

                              AND    rownum <2)

    || ';' ||   (select X3.RC_DESCR_SS from PS_RC_CA_TY_TBL X3,PS_RC_CASE Y3