Problems with video playback DB500+gemini (cifs)

[gb2]

This problem happens with a DB500 and Gemini_104_500 image.
I don't know if it's the DB that's defective or if it's a bug in the image.

If I telnet into the db (after booting), I see that I have almost 10MB free.
After mounting a remote cifs dir, I playback a recording, and I get video and audio. ( they're in sync. )
The amount of free memory goes down very fast, and after a while, I get only +-500kb free...
and then (in a totally random way) the screen goes black... but the audio continues...
What's strange is that the TV OSD shows up.. which means that there's no signal comming from the DB... which might point to a hardware problem...

If I press MENU and OK, to go back to TVmode, It does change, and I get audio, but I nolonger get any video... In order to "recover" I have to reboot the DB...

did anyone experience this?
any ideas on how to solve it?

thanks