What is the operating system on your computer?

Windows XP (service pack 1) may not handle file size greater than 2Gb (due to a bug/unsigned integer).

Win/XP(sp2/sp3) and later can handle files > 2Gb.

Most 'modern' OS's can now work with 12 EB files (but DVD capacity has yet to get there).

Linux, of course can read and write most file systems (ISO and UDF included) and most DVD recording formats/systems (including DVD-RAM and DVD-ROM, and the more common formats DVD-R and DVD+R)

Perhaps, your operating system is 'too old' or your 'Nero Express' version is too old.

;-)