I am using Premiere Elements 14.1. I have encountered a very strange issue when trying to create an ISO image of a DVD disc, fitting contents to available space (space required is 4.35 GB at 5.12 Mbps bit rate), which should easily fit on a 4.7 GB DVD. I get the message "Insufficient disk space for burning", even though the hard disk I am using has over 1.5 TB of free space! All of the Premiere Elements working folders are on this drive. I cleaned out all applicable Premiere Elements work folders prior to attempting to create the ISO image. I tried opening the same project on a different computer and same build of PE, with the same result.
I believe I've discovered a freak bug in PE Version 14.1 (20151208.daily.895401). The exact length of the movie is 1:50:16:08. I discovered that if I increase or decrease the length of the video by just 1 frame, I no longer get the error, and am able to successfully create a DVD ISO image!