Script done... Function won´t work...

Once again, ;-)

The script is finally done i hope ...

i can create my function.... no problem
but when i'm calling it up with a
SELECT zufall(); statement pgAdmin
tells me there is no function with that name...
although its listed in my function list as zufall!!!! ...



SOURCE:
create or replace function zufall(int4) returns text as '
declare
  anzahl      alias for $1;
  i           int4;
  zeichen     char(1);
  zufallstext text;
  entries     int8;
begin
  loop
    zufallstext := '''';
    for i in 1..anzahl loop
      select chr(trunc((random()*26)+65)) into zeichen;
      zufallstext := zufallstext || zeichen;
    end loop;
    SELECT count(*) into entries FROM se_errorcode
      WHERE entry = zufallstext;
    EXIT WHEN entries = 0;
  end loop;
  return zufallstext;
end;
' language 'plpgsql';