e-8709 Communication Error on CDJ-2000

Hello Pioneer community,

I have put my tracks via Rekordbox on a clean and correct formated USB-stick. But when using is on the CDJ-2000 I get the error-message after playing a couple of tracks. The screen reads: E-8709: COMMUNICATIONS ERROR

When using this USB-stick in a newer CDJ-2000NEXUS I can play all night with this device.

On the CDJ-2000 I have the latest firmware running (4.33) but the problem resists. What is wrong and is there a way to solve this?