First thing I would recommend is checking the printing layout and paper size you're using. To do this, go to Print > select printer > Preferences > Advanced> Layout. Make sure the proper size and paper is selected in the options menu. After this procedure, try printing again. If you encounter the same error, reinstall the application, then repeat the process.
Additionally, this could be a problem with the hardware of the printer or with the software itself. Make sure to turn everything on default when using the Labeling Software (default values for settings).
If you require official website, contact the developers through the following link: http://goo.gl/Zx5h67