PhoneBurner uses the disposition buttons at the bottom of your dial session screen to progress through the dial session. When you click on a disposition button, the dialer will move on to the next contact for your dial session.
If you find that all of your disposition buttons, the Dialing Set buttons ("No Answer" or "Fax Machine") or Live Answer buttons ("Interested" or "Do Not Call") are greyed out and you can't select them after a call, check your disposition settings with these steps:
1. Go to Call History
2. Click on Dial session settings
3. Click on Dispositions and edit your dialing set
Check to make sure that there is not a voicemail assigned to each button as this will cause them to not work if there is no answer on the line.
Unless the button that you are editing is a Voicemail button, the voicemail option should be set to "None".