dcs Purcell upsampler/Delius DAC interface

I need some help! I am using my upsampler, fed by an iMac computer, to upsample my CDs to DSD. The sound is sublime, definitely better than upsampling to 192k. Yet, I keep getting a message on the delius dac of "no wordclock". Can some saavy dcs person tell me what I have done wrong. I have worked with the factory and have had some success in getting the upsampling to DSD to work but not the clock.

Help! and Thanks!