If you are using Barcode Professional for ASP.NET dll i.e. Neodynamic.WebControls.BarcodeProfessional.dll in your ASP.NET website and you host it in a server which is configured for Medium-Trust level (like the one offered by GoDaddy.com Shared Hosting servers), then the barcode dll you used for development will not work on such scenario. That’s because by default, you add a reference to our barcode dll which was not designed for trust level restriction.
When you install Barcode Professional for ASP.NET in your dev machine, the installer package provides a couple of Neodynamic.WebControls.BarcodeProfessional.dll files and one of them was designed and built to be used in Medium-Trust level websites. By default, such dll can be found at [BarcodeProInstallDir]\Redistributable\For .NET 2.0-3.5-4.0 (Medium-Trust)
So, what you need to do is just to deploy that dll in the BIN folder of your website hosted in the shared server.