When using the Microsoft Office 2007 UI capabilities provided as part of DotNetBar Suite for Windows Forms, be aware that the DotNetBar Suite license grants you no rights to the Microsoft office 2007 UI. For more information and to obtain such license visit http://msdn.microsoft.com/officeuiThe Office 2007 User Interface License provided by Microsoft you can obtain FREE of charge on the URL specified above. You can also read more information about the Office 2007 Licensing program here.
Please note that DotNetBar Suite provides you with the wide range of options on how to structure and design your user interface. While DotNetBar helps you greatly with Office 2007 User Interface guidelines compliance you still should ensure that your application indeed complies with these guidelines.
If you decide not to use controls above in your application then no license for Office 2007 UI is needed.