Hey,
first of all install the newest driver for you soundcard. For the u-44 Mix soundcard you can download it in the download page of this forum.
http://forum.mixvibes.com/downloads.phpAfter installing you must connect you CD Players with the soundcard in the Input field. The output section go through your Mixer.
On the DVS software you select now the Asio-Driver for you soundcard. And set up your inputs for CD. (The easiest way is starting the Installation assistant inside of the DVS software). After that everything should work.
If not please post a config report when everything is running and also a detailed description of you setup.
I hope it wil help you
regards
Christian