What format are the aiff files in? I would think pcm would work but if they're compressed you may need to convert them first.
WARNING - If your DVD was copy protected we can't talk about how you cracked the copy protection or what software you used (see TOS 9). But of course, it's OK to talk about converting AIFF to something else. So, you're not trying to play DVD-Audio, you're trying to play AIFF or ALAC... I don't use AIFF, and I've never used ALAC, but I'm sure iTunes supports ALAC. I just made an AIFF,* and it did play it in iTunes.What software are you using to convert the AIFF to ALAC? Or, did you try directly making an ALAC with your ripping software (which we can't mention)?Do you know any format details of your AIFF file? It is it "regular" uncompressed PCM? Is it a multichannel file (5.1 etc.)? I'm just guessing that multichannel might be a problem. If there is a stereo track on the DVD, you might try ripping that. Or, you can try converting it to stereo. * I used GoldWave to convert a WAV file to AIFF.
...and It says it has 6 audio channels.