Symptoms
Radio buttons do not print when printing from a browser.
Diagnoses
This is a known issue when printing from a browser. There is a feature request to implement an out-of-the-box printing functionality for Smartforms.
Resolution
To print the form from a browser, choose to print background images and colors, which will correctly print the radio buttons. Alternately, you can use the "Save as PDF" control and print from the PDF.