Your's looks similar to my old Pioneer DV-563a, which plays DVD-A without issue. So, maybe get a TV hooked up to your DV45A, and go into the setup menu. Make sure that the needed formats are selected, and are using the correct output mode.
Also, unlike CD playback, DVD-A & SACD only output via analog RCA connectors. No Toslink or Coax digital out, due to copy protection issues. So, you have to use the analog connections, for DVD-A.
Good luck!