If the install path has spaces in it, such as "C:\Program Files\DVDStyler", then DVDStyler will show an error when generating the DVD, that indicats that it can't find ffmpeg_vbr. From what I read online, it has to do with quotes needing to be passed when calling this command. This error occurs when running DVDStyler on Windows XP. The temporary fix is to install it to a path without spaces in it, such as "C:\DVDStyler".