Checkbox controls not displaying correct database value

I'm having trouble getting checkboxes to bind correctly with a database (using VS 2010; WPF 4.5).  If I use XAML to bind, no problems.  But, if I try to bind to a Boolean entity property using code such as...

Binding bind =newBinding(path);

bind.Mode =BindingMode.TwoWay;

((CheckBox)uiElement).SetBinding(CheckBox.IsCheckedProperty, bind));

the checkbox will fail to display the database value on rendering, and won't persist back any change when clicked.  Oddly, I have other controls (e.g., textboxes) that use analagous binding code - these work fine!  I checked that the entity being bound contains the correct value.

In searching for solutions on the internet, I notice that there have been issues with checkboxes (and other ToggleButton controls) in the past, but I've seen nothing about wpf 4.5 having such issues.

Where am I going wrong here?  Suggestions?

Thanks

Eric