ORA-06502: PL/SQL: numeric or value error: character to number conversion error

Dear All,

The following procedure i need to update the ACTIVITY_PERIOD_BEG<SYSDATE-10 , 'ACTIVITY_PERIOD_END>SYSDATE+10

please Help me....

CREATE OR REPLACE PROCEDURE  ALLOW_PERIOD_ONLY

AS

    v_sysdate varchar2(10);

    v_from_date varchar2(10);

    v_to_date varchar2(10);

BEGIN

Select sysdate into v_sysdate from dual;

SELECT FIELD_VALUE into v_from_date  FROM  MCA_SYSTEM_PARAMS  WHERE FIELD_NAME='ACTIVITY_PERIOD_BEG';

SELECT FIELD_VALUE into v_to_date  FROM  MCA_SYSTEM_PARAMS where FIELD_NAME='ACTIVITY_PERIOD_END';

If trunc(to_date(to_char(v_from_Date,'dd/mm/yyyy'),'dd/mm/yyyy')) <> trunc(to_date(to_char(v_sysdate,'dd/mm/yyyy'))-10) Then