> > The "can't dup Fixnum" error what I have mentioned in my previous post
> > is caused by a change in tk.rb.
>    (snip)
> > This change causes the fixnum problem in class TclTkExtIp's constructor.
> 
> Sorry. This changes default Tk.appname from 'tk' to
> current command/script name.
> I didn't observe 'tcltk-ext' library on 1.8.2.
> As you point, it cannot work with 1.8.2.
> Please adopt the following patch.
> 
> diff -u ../tcltk-ext051/tcltkextlib.rb ./tcltkextlib.rb
[...]

I patched it, and it works now. Thank you!

Ferenc