Gtk::TreeRow set_value segmentation fault

[Benjamin Waldher <b waldher comcast net>]

I can't seem to set the value of a cell after creating a table. Here is 
a sample of the code that causes problems:

SetWindow::SetWindow(BaseObjectType *cobject, const 
Glib::RefPtr<Gnome::Glade::Xml>& refGlade){
   refGlade->get_widget("bondCoeffsView", bondCoeffsView);
   bondCoeffsModel = Gtk::ListStore::create(bondCoeffsColumns);
   bondCoeffsView->set_model(bondCoeffsModel);
   Gtk::TreeRow br = *(bondCoeffsModel->append());
   bondCoeffsView->append_column("#", bondCoeffsColumns.num);
   bondCoeffsView->append_column_editable("Coeff 1", 
bondCoeffsColumns.coeffs[0]);
   bondCoeffsView->append_column_editable("Var", 
bondCoeffsColumns.isVars[0]);
   bondCoeffsView->append_column_editable("Coeff 2", 
bondCoeffsColumns.coeffs[1]);
   bondCoeffsView->append_column_editable("Var", 
bondCoeffsColumns.isVars[1]);
   bondCoeffsModel->signal_row_changed().connect(sigc::mem_fun(*this, 
&SetWindow::on_bondCoeffsModel_changed));
}

void SetWindow::on_bondCoeffsModel_changed(const Gtk::TreeModel::Path& 
path, const Gtk::TreeModel::iterator& iter){
   int n = 1;
   for(Gtk::TreeModel::Children::iterator chIt = 
bondCoeffsModel->children().begin(); chIt != 
bondCoeffsModel->children().end(); chIt++){
       chIt->set_value(bondCoeffsColumns.num, n);
       n++;
   }
}

The cause seems to be the 'chIt->set_value(columns.num, n);' line. All I 
get is 'Segmentation Fault.' Valgrind outputs this:

Process terminating with default action of signal 11 (SIGSEGV)
Access not within mapped region at address 0xBE4BBFEC
 at 0x48EB82c: g_type_check_value (in /usr/lib/libgobject-2.0.so.0.1400.3)
Stack overflow in thread 1: can't grow stack to 0xBE4BBFE8