% Autor:
% Fecha: 02/02/2010

:- use_module( library(pce) ).
:- use_module( library(broadcast) ).
  name_of(a,ah).
  name_of(b,bh).
  name_of(c,ch).
  name_of(d,dh).

:- pce_begin_class(name_item, text_item).

variable(id, any, get, "Id visualised").     % name, type, access,
[comment]

initialise(NI, Id:any) :->  name_of(Id, Name),
                            send_super(NI, initialise, name, Name,
message(NI, set_name, @arg1)),
                            send(NI, slot, id, Id),
                            listen(NI, name_of(Id, Name), send(NI,
selection, Name)),

unlink(NI) :->  unlisten(NI), send_super(NI, unlink).

set_name(NI, Name:name) :->  get(NI, id, Id), retractall(name_of(Id,
_)),  assert(name_of(Id, Name)),  broadcast(name_of(Id, Name)).

:- pce_end_class.

When I compile and create an object from this class, and try to use
set_name method, I find an error:

% library(win_menu) compiled into win_menu 0.00 sec, 11,760 bytes
% library(swi_hooks) compiled into pce_swi_hooks 0.00 sec, 2,024 bytes
% c:/users/ron/appdata/roaming/swi-prolog/pl.ini compiled 0.00 sec,
380 bytes
Welcome to SWI-Prolog (Multi-threaded, 32 bits, Version 5.8.2)
Copyright (c) 1990-2009 University of Amsterdam.
SWI-Prolog comes with ABSOLUTELY NO WARRANTY. This is free software,
and you are welcome to redistribute it under certain conditions.
Please visit http://www.swi-prolog.org for details.

For help, use ?- help(Topic). or ?- apropos(Word).

1 ?- consult('C:/project/workflow prolog/modularity/name_item.pl').
%  library(quintus) compiled into quintus 0.02 sec, 10,768 bytes
%  library(pce) loaded into pce 0.03 sec, 197,788 bytes
%  library(broadcast) compiled into broadcast 0.00 sec, 3,944 bytes
% C:/project/workflow prolog/modularity/name_item.pl compiled 0.05
sec, 206,752 bytes
true.

3 ?- new( NIA, name_item(a) ).
NIA = @8394732/name_item.

4 ?- send( NIA, set_name, newName ).
ERROR: Arguments are not sufficiently instantiated

what's the reason for this error (ERROR: Arguments are not
sufficiently instantiated)?

thanks in advance for your help.

?-  new( NIA, name_item( a ) ),  send( NIA, set_name, newName ).

the results would be different.

ERROR: retractall/1: No permission to modify static_procedure `name_of/
2'

:- dynamic(name_of/2).

Cheers,