Help! Another DJM900 record to audacity thread

Apologies for yet another post on this subject - I have read the previous posts, but I still can't get any audio to show on the audacity waveform when I record, so I'm obviously missing something.

Setup and settings:

CDJ2000 Nexus - 2 x connected by digital coax to DJM 900 to channels 2 & 3.  Default 24 bit output on CDJ

DJM900 - club setup default 96khz sampling rate and default -19db recording level

DJM900 utility on MacBook Pro (mavericks) - inputs show as digital, output for channel 1/2 set to REC OUT and USB output level to -19db.

USB connection direct to mac, not via a hub

Audacity: Recording device set to DJM900 and 2 channels.  Quality settings: sample rate set to 96khz and 24 bit sample format.

I've tried all the variations on the sampling rate, digital output on both CDJ, DJM and Audacity (CDJ to 16bit to match underlying music to avoid down-sampling, analogue cable to CD input on DJM, 44100khz sample rate and 16bit on audacity), but still no sound shows up on the waveform.  I have also tried setting out channels on the DJM utility to REC OUT, but still no success.  I have also rebooted everything several times after trying various new settings.

I have no problem recording out when going to a line in 3.5mm on another PC (latest MacBook Pro headphone socket doesn't double as a line in).  Also had no problem recording via USB when I use Traktor (although I don't use it anymore).

Any help very gratefully received - I've read so many posts and watched a lot of YouTube vids, and it all seems very easy, so I'm obviously missing something simple!

Thx