recording with audacity using DJM2000 cj2000nxs

First off I've read the previous post by @pulse and have done exactly what he illustrated in his youtube vid. I'm using a macbook with the current version of audacity. The DJM 2000 and CDJ 2000nxs is all connected via link and RCA. I'm trying to record my mixes and I'm trying to get clarification on how I can connect the DJM via USB like how everyone else has been doing. I connected with the included usb cable and it recognizes the DJM I also used RCA to 1/8" connector to built in input. That's what I've used to record mixes before and it's okay the sound is a little distorted. I know I probably need to mess with recording levels. Anyway I guess my question is when I open audacity and go to preferences I'm able to select DJM2000 as source but when I press record it states ERROR while opening sound device. Please check the recording device settings and the project sample rate. What am I missing here. I have the USB plugged in and I also have the RCA to 1/8" plugged in from REC OUT. Do I even need the RCA? Seems like the only way for me to record or get sound to audacity is through the RCA.

Also I apologize for the redundancy of this post question. But thank you in advance to helping me solve this mystery.