If you haven't change any assembly information then there's a chance that visual studio's hosting process is causing the problem. There's also a chance that you need Visual Studio to revise your license file since you are using 3rd party control. Follow the following step:
Goto Project Menu and click Project Properties. Then click Debug tab. There you'll see Enable the Visual Studio hosting process checkbox. If it is checked, un-check it. Then goto Build Menu and click Clean Project or Clean Solution. After that try re-running the project.
If that doesn't solve it, try following:
Goto Project Menu and click Show All Files. This will display all hidden files from the solution explorer. Now find the license.licx file from the solution explorer. Right click it and select Exclude From Project. This will allow Visual Studio to recollect information about the 3rd part DLL and create new license file automatically. Try running the project again.
If that doesn't solve it either, try following:
You can delete obj and bin folder from your project directory. This will create fresh files for you. But be sure to copy Local Assemblies from the Bin folder first, such as DotNetBar as you are using. You can then add it again from the Project Properties and then going to References Tab.
Right now, I can just think of these ways as these two solve the problem for me when I am using any 3rd party control. I will think about more if these doesn't solve your problem.