My friend and I have both been using DVD FLICK with great success on a Windows 7 platform. Yesterday, we both suddenly got the same problem -- at the "finalize" stage of the DVD creation process, with "create ISO" selected, Avast pops up and says it may be malware, and then the ISO creation aborts with message "-1 from finalize." I have the full code of the error message if that will help.
They like sooo many other software makers hide that stuff away on purpose or word it so you don't recognise it