Link Export to XDJ 1000 mk2

Hi,

i'm using 2 xdj1000 mk2 and now i tried to connect them with USB to my macbook to use the "link export" function. After connecting arrives the link button below on the left side of rekordbox and i can see the 2 players. But now, when I want to load a track in one of the two player it doesnt work. It is loading but than comes a error message on the player (E8302). i tried it also with 2 other macbooks and with this it works perfectly. now i want to ask you, which settings i have to take that it will work with my macbook. thx for your help

(firewall is off, new rb version, yosemite)