hy
is the dvi-hdmi cable that comes with the dm800 a standard cable? because i tried with a dvi-hdmi cable that i have here at home to use with my pc and it won't work at all... i mean not video and no audio 
hy
is the dvi-hdmi cable that comes with the dm800 a standard cable? because i tried with a dvi-hdmi cable that i have here at home to use with my pc and it won't work at all... i mean not video and no audio
there is maybe a difference between the cables.
you have to use a DVI-D cable with your dreambox. try the inlcuded cable, it will work!