4-bay-hdd enclosure gets interrupted from time to time (no free space?)

[sylvio2000]

I have a 4-bay enclosure from Fantec which is connected with the PBO via usb. Its filled with 4 hdds from 1-1,5 TB (every hdd is filled up with files). No internal hdd.

If I watch a movie after some time (very different: sometimes 5 Minutes or 20 Minutes or 60 minutes) it stops and I see the home screen. Then the usb connection is lost and is getting scanned again. Sometimes even the hdmi signal gets lost and I have to restart the PBO.

One time I could see a message saying there is less than 200 MB space left on hdd and I have to free up some space.

Could this be the problem? Is there not enough free space to play a movie? (I already changed the usb cable)