I am having this problem as well. The disk burns and everything, no error message is given, the eject works properly et al. then the DVD is just empty. Nada. I made sure that no other programs were running at the same time to upset the burn process, no Norton, no ICQ/Messenger, not even the screensaver. I used the program quite successfully to burn a CD-R so the burner is working (at least for CDs).
Operating system Windows XP, Burner Sony DVD RW DW-U12A, version 100, just downloaded on Feb 08.