Possibly nero splits large files without telling you? Maybe you were using a different drive when you did this before?
It is very common to use a file splitter in these circumstances, and rigging the system to play each file contiguously.
4GiB is often quoted as a practical limit for udf file sizes. But I think the theoretical limit is in the terabytes.
The best bet is to use the CLI tool (wodim or cdrecord) in verbose mode and see what it says.