Q: "file is too big for the disc, and do I still want to burn?".....when I click "yes" it just cancels the whole operation.
Please use expert interface and select 3.0GB as D5 Disc Size in Advanced Seutp, then try again. Or select "D9 to D5 movie only disc copy" function. If you use 1:1 option to backup a D9 movie, you need a D9 blank disc (8.5GB) to make a 1:1 copy.