What computer operating system?
Is the burner recognized if you set for Export & Share/Disc/AVCHD instead of DVD?
Are you running the programs as administrator (from user account with administrative privileges)? Even if you are, please right click the desktop icon of the program, select and apply Run As Administrator, and determine if the burner is recognized in the Destination field.
What other burn software do you have installed on your computer?
Often the most effective means is to do an uninstall, free ccleaner (regular and registry cleaner parts), and then reinstall with antivirus and firewalls off.
And, if your computer is not using an Intel HD Graphics 2000 and higher video card/graphics card, remove the check mark next to the Hardware Acceleration preference under Edit Menu/Preferences/General.
Please consider and let us know the outcome. Any questions or need clarification on any of the above, please do not hesitate to ask.
Add On...we can talk about taking the ,iso to disc next.