That was my thought too, as I thought that file had to be unzipped. I'm even sure that I read somewhere that file had to be unzipped prior burning, but unzipped file simply did not work for me. I tried V32, V29, etc. Not one worked if unzipped prior burning. For some reason, unzipped file would create a sub-folder or in some cases multiple sub-folders, which may have prevented NAVI reading actual software.
However if you upload unzipped file in to ImgBurn, it seems that it would unzipped via ImgBurn during burning process.
BMW MKIV Navigation Custom OS & 2012 DVD Map with Speed Cameras

Once correct CD was installed, right away NAVI Screen came to life with message RE; software being installed and then a running progress bar. I think the entire process took less than 2 min.
Just like in this video: BMW V32 MKIII MKIV Software Update, How-To - YouTube

If you want, I can burn you V32 or older software.