Using v2.5.1 with OS 10.4.11 on an iBook G4, in the burn phase the progress bar immediately goes from "preparing" to "closing the session." It created the audio_ts and video_ts folders in the temp folder but did not burn a playable DVD-A or save a usable image. I was able to make a proper image from the audio_ts and video_ts folders by invoking mkisofs with the syntax shown on the DVD audio tools page at http://dvd-audio.sourceforge.net/howto.shtml. (The log of the Burn session showed different syntax.) Burning this image with Disk Utility produced a playable DVD-A.