What was the last picture you took with your camera,
On my way to work Thursday morning at about 6.35am, and I had the D3200 with me, and noticed some very nice colours in the sky, so got to a good vantage point, and took this shot.
I did notice that you are exporting 456 files to cd/dvd, not done it that way before so not sure on the setting.
I did spot this, when I clicked on the thumbnail at the bottom of the screen, to burn full size jpegs.
I am using lightroom 5.7, so not sure if its the same as yours, when I go to export I can adjust the size of the finished file. make sure you don't have the limit file size box ticked.