Reboot when browsing a big UPnP server

I've just received the new MED500x2 to replace my previous MED500x.
I didn't install an internal HDD till now.

Product & firmware version: Mede8er MED500X2 F/W: v1.0
Video: HDMI output > Toshiba 40" Led HDTV 40SL736FC thru HDMI 1.4
Video setting: 1080p 60Hz,24Hz ON,16:9
Audio setting: HDMI Passthrough / Night mode OFF
Ethernet 1Gbps (Gigaswitch Peabird, ADSL Gateway Freebox v6, NAS DLink DNS-313, AP Cisco 1130AG )
USB Kbd: RF keyboard Keysonic KSK-3200 (FR)

Media Source: Gigabit ethernet > DNS-313 UPnP server
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From library, the MED500x2 reboots when I try to browse the content of the UPnP server of my DNS-313.
The path is: UPnP/DNS-313/Video/Folders/DivX

The previous version MED500X v4.04 has no problem to do the job.

My DNS-313 is fitted with a 2TB HDD that contains a collection of about 1700 movies. Each one is included in a folder that holds the name of the movie, which make about 1700 sub-folders in the DivX directory. The movie itself is always called Film.xxx where xxx stands for AVI, MKV, MP4, ISO and so on. If the movie counts several volumes they are labeled Film.CD1.avi, Film.CD2.avi..., the same for subtitles which are named Film.en.srt, Film.fr.srt... Sizes for movies range from 100MB to 8GB.
For the naming convention I've adopted and the limitations of the DNS-313, I have to use "Folders" instead of "All videos" because all my movies have same name.