error converting an Oracle procedure to a PostgreSql function in the pl / pgsql language

I have adapted the code, but the following error appears:

  

ERROR: relation "fields" does not exist CONTEXT: compilation of PL / pgSQL function "p_grava_log"

CREATE OR REPLACE FUNCTION F_GRAVA_LOG (
  TIPO character varying,  
  C_TABELA  character varying,  
  C_CAMPOS_CHAVE  character varying,  
  C_CHAVES  character varying, 
  --VALOR DO CAMPO CHAVE  C_USUARIO NUMERIC,  
  C_MODULO  character varying)  RETURNS TEXT AS    

    $BODY$

  DECLARE 
    V_CAMPOS  character varying(6000);    
    V_SQL  character varying(32000); 
    CAMPOS RECORD;
    CAMPOS1  CAMPOS%ROWTYPE;


  BEGIN 

    FOR CAMPOS IN 
    SELECT column_name 
      FROM information_schema.columns 
     WHERE table_name = C_TABELA
     ORDER BY ordinal_position LOOP      
      V_CAMPOS := V_CAMPOS || CAMPOS.COLUMN_NAME || ','; 
    END LOOP; 
    V_SQL := 'INSERT INTO ' || 
             ' l_'||C_TABELA||' (' || V_CAMPOS || ') ' || 
             '  SELECT ' || V_CAMPOS  || 
             '    FROM ' || C_TABELA || 
             '   WHERE ' || C_CAMPOS_CHAVE || ' = ' || C_CHAVES; 

     EXECUTE  V_SQL; 
       Return V_SQL;     

  END;  $BODY$

LANGUAGE plpgsql