@Dzr G > The problem you are encountering here is that you are using two sound cards (2x CDJ2000) but Traktor encounters issues trying to support these. However, there is a simple workaround. Please download and install ASIO4ALL.
When you have this done you can then select the sound card driver as the Audio Device and route the output to the respective sound cards (i.e. the CDJs) with the ASIO4ALL interface.