This error sometimes occurs because the Musicnotes Player installed isn't able to use our music character font, "Doremi." When you installed either the Player or the Viewer, this font was automatically installed on your computer. However, it might not be accessible if too many fonts already exist on your hard drive.
This problem most often occurs on systems that have over hundreds of fonts installed. Most versions of Windows can only successfully recognize a few hundred fonts before they must ignore all others. To access "Doremi" and many other fonts, you may need to delete some of your least commonly used fonts, or get an advanced font management utility.
After doing so, you may install the Musicnotes Player again to avoid the error.