[PD] problem creating [cnv] with messages

[Federico]

hi,

I am dynamically building an interface, with canvases:

[pd loop]
 |
[obj $1 $2 cnv 12 24 12 send_foo $3 0 0 7 0 10 -166441-33289 0(
 |
[s pd-my-subpatch-name]

but when I go in edit mode and try to open the properties dialog, I see 
this error in console:

wrong # args: should be "pdtk_iemgui_dialog id mainheader dim_header wdt 
min_wdt wdt_label hgt min_hgt hgt_label rng_header min_rng min_rng_label 
max_rng max_rng_label rng_sched lin0_log1 lilo0_label lilo1_label 
loadbang steady num_label num snd rcv gui_name gn_dx gn_dy gn_f gn_fs 
bcol fcol lcol"

what's the problem?
for the [cnv] params I looked at a .pd file source...
I am running miller pd-0.39.2, and this happens on all platforms

thanks in advance

-- 
Federico