Can you change the single quotes enclosing the parameter names in double quotes. Single quotes are not allowed according to the syntax rules:
select_kpi = SELECT date, SUM(kpi) AS kpi FROM "sap.sample.db::CVKF_BUSINESSLOGIC" ( PLACEHOLDER."$$IP_STARTDATE$$" => :lv_from_date, PLACEHOLDER."$$IP_ENDDATE$$" => :lv_to_date) ) GROUP BY date;