Using two computers with cdj2000 nexus. One running Traktor, the other Rekordbox

I'm currently having problems running two laptops connected to the cdj2000 nexus. One laptop is running Traktor, the other Rekordbox. The problem is, I can't drag tracks into either of the cdjs using the rekordbox software.

I can still access the music on the laptop running Rekordbox using the screens on the cdj, but when I try to drag a track onto either of the decks with rekordbox, it won't let me do it.

Any help would be greatly appreciated.