TclTk library loading (whole version) Linux

Hello;

Well, I'm afraid this is the second related problem I report in two days
(I'm sorry for this)

I've programmed a tcltk interface for a model and it includes a
comboBox. The comboBox widget comes with the "BWidgets" library of Tcl/Tk.

 It works all perfectly with the windows R GUI (with the help of Prof.
B. Ripley), following the advices in ?Startup, but I would like that it
also could work under Linux. I've got a complete TclTk8.4 installed and
also BWidgets, and I could swear that the complete Tcl libraries could
be loaded at least once, because I saw a message like "Tcl 1.7" or
similar under R.

Now I don't receive the message anymore and it cannot find BWidgets
under R. So I'm not even sure that I'm loading the whole tclTk Library
anymore(instead of the subset that comes along with R)

I've got libtcl8.4.so and libtk8.4.so in /usr/lib
My .Renviron file contains:

MY_TCLTK=yes
TCL_LIBRARY=/usr/lib/tcl8.4

an in my R session:
------------------------------

Sys.getenv("MY_TCLTK")

MY_TCLTK
   "yes"

Sys.getenv("TCL_LIBRARY")

      TCL_LIBRARY
"/usr/lib/tcl8.4"

tclRequire("BWidgets")

[1] FALSE
Warning message:
Tcl package 'BWidgets' not found in: tclRequire("BWidgets")
---------------------------------

Please, some how uses BWidgets could tell if I'm doing something wrong
in these steps? I've just installed ESS (Emacs Speaks Statistics), could
this be a source of problem?

Thanks to all, and best regards

Javier