Hello:
InfoPath 2007 has a Design Checker task pane that can help you find errors. Open your form in design mode and open the Design Checker -- if you have unbound controls, you'll see them listed there.
You can also check with every control is bind to the data source or not. For this you need to keep your cursor position at the top and you have select ‘Data Source’ in task pane. Then start clicking on ‘Tab’ in keyboard each time its moving cursor position and it will shows the binding of field or group to your data source. By doing this you will get what are the fields not binds to your data source. For these fields you need to rebind it or remove it.