trouble creating gtknotebook in libglade

[Rob Benton <rob benton conwaycorp net>]

Hi everybody.  I'm new so go easy on me.

I've just started working with gtk and glade.  I've run into a problem 
trying to create gtknotebook widgets.  When I use glade to build the C 
source files of just a window and an empty notebook widget, I have no 
problems.  But using the same xml and libglade I keep getting this error:

Gtk-CRITICAL **: file gtknotebook.c: line 5041 
(gtk_notebook_set_tab_label): assertion `GTK_IS_WIDGET (child)' failed

I'm on Debian using packages:
libgtk2.0-0 version 2.4.3-3
libglade2-0 version 2.4.0-1

Am I doing something wrong?