update problem in triggers

I am having with this simple trigger i wrote, worked when i created it
but now i get this error "Stack depth Limit Exceeded"

If someone could tell me what i am doing wrong i would be greatfull

Trigger

CREATE TRIGGER "updateKeys" AFTER UPDATE
ON "projects"."resource" FOR EACH ROW
EXECUTE PROCEDURE "projects"."setParentKeysResourceUpdate"();

Function

CREATE OR REPLACE FUNCTION "projects"."setParentKeysResourceUpdate" ()
RETURNS trigger AS
$body$
declare
projectcursor refCursor;
prop RECORD;
begin
if new.fkproject is null then
open projectcursor FOR SELECT * from projects.component
WHERE projects.component."primary" = new.fkcomponent;
FETCH projectcursor into prop;
update projects.resource set fkproject = prop.fkproject,
fkproposition = prop.fkproposition, fkjob = prop.fkjob where
projects.resource."primary" = new."primary";
close projectcursor;
end if;
return null;
end;
$body$
LANGUAGE 'plpgsql' VOLATILE CALLED ON NULL INPUT SECURITY INVOKER;