2000nxs2 E-8309 LINK ACCESS ERROR on usb link export

Hi,

I got two 2000nxs2 linked with pro-link. (FW 1.60, recordbox 4.3.0)

when connecting my macbook with OSX 10.9.5 via usb directly to one of the players and running recordbox in export mode the link button in recordbox appears. If I click it it rb shows that the link is established (I see two nxs2 at the bottom), but on the cdj`s the message "E-8309 LINK ACCESS ERROR" appears briefly. I am not able to drag any tracks in to the 2 players at the bottom. I can link and unlink to no avail.

I tried it with nxs2 selected as audio interface in osx and rb, and with built in audio selceted. Still same problem.

Cheerz