With a new update to Firefox an Adobe Flash protection mode has been added that may not allow you to print. If this is happening to you there are two things you can try:
1. You can use a different internet browser like Internet Explorer or Chrome
2. You can try changing the settings in Firefox:
Click on the menu button and choose Add-ons.
The Add-ons manager tab will open.
Find Shockwave Flash and select options next to it.
Disable 'Enable Adobe Flash protected mode".
Try printing again and let us know if you continue to have issues.