sql - Run plpgsql program to update the data in table -

i using postgres 8.4. want update data using plpgsql , cursor. when try run plpgsql generates error.

create or replace function updatescore()  returns void $$ declare singletopiccriteriapercentage   decimal(6,10); sitepercentage          decimal(6,10); singlesitecriteriapercentage    decimal(6,10); totalsocre          decimal(6,10);  cursor1 cursor select id sitereviews order id; cursor2 cursor select weight rating sitereviews_ratingcriteria site_id = id;  id              sitereviews.id%type; weight              sitereviews_ratingcriteria.weight%type;  begin singletopiccriteriapercentage := (10 / 120) * 100; sitepercentage : 0.0; singlesitecriteriapercentage := 0.0; totalsocre := 0.0;  open cursor1; loop fetch cursor1 id; exit when not found;     totalsocre := 0.0;      open cursor2;     loop     fetch cursor2 weight;     exit when not found;         sitepercentage := singletopiccriteriapercentage * weight;         singlesitecriteriapercentage :=  (sitepercentage / 100) * 10;         totalsocre := singlesitecriteriapercentage + totalsocre;     end loop;     close cursor2;      update sitereviews set weight = : round(totalsocre)  current of cursor1; end loop close cursor1; end; $$ language 'plpgsql' 

following error when try run program :

error: not load library "c:/program files/postgresql/8.4/lib/plpgsql.dll": application has failed start because side-by-side configuration incorrect. please see application event log or use command-line sxstrace.exe tool more detail.  sql state: 58p01 

it postgresql installation not complete or broken. in older postgresql installators plpgsql optional. so, please, check installation.