Problem with plpgsql installation!!!

Hi,  I have a problem   installing  "plpgsql" in  postgreSQL 7.4.6 on linux.
Those Scripts were create succesfull but when i try to create some "store
procedure(function)" no gererate errors, no generate nothing  in the pgadmin
III, i don't  know what is the problem.


 '/usr/lib/postgresql/plpgsql.so'  exist!!

those are the script:


CREATE FUNCTION public.plpgsql_call_handler () RETURNS language_handler AS
     '/usr/lib/postgresql/plpgsql.so' LANGUAGE 'C' VOLATILE;



CREATE TRUSTED PROCEDURAL LANGUAGE 'plpgsql'
  HANDLER public.plpgsql_call_handler;



help me please.

thanks.