Well I've tried a straight HDMI to DVI cable and a brand new HDMI cable + brand new HDMI to DVI adapter and nothing changed - it still looses video after a few minutes of playing.
It almost acts like it's discovering something it doesn't like (maybe copy protection) and then it quits.
We watched the HD-DVD of Transformers last night through the component connection and it played fine but HD dvd was only half the reason for getting this player - being able to up convert the 200+ standard dvds we have was the other and without a HDMI connection apparently we can't do that.
Yes, that's a big reason why I got my HD DVD player - to also upconvert the many standard DVDs I have, and rental DVDs of movies that won't be out in High-def for many years.
And, it's not Toshiba or HD DVD that's the problem with upconverting - in the industry's stupid copy-protection "wisdom", standard DVDs can only be upconverted via a digital connection (DVI or HDMI) secured with HDCP. Both Blu-ray & HD DVD planned to also require this for high-def, but delayed implementing it until 2011 or 2012 because of the millions of HDTV's with only analog component inputs. So, for the next few years you can enjoy High-def without HDCP, but to upconvert you need DVI/HDMI with HDCP.
I'm sure your HDTV has HDCP - as I've said, it either works or it doesn't work. If the HD DVD player ever loses the HDCP connection, it doesn't just fade out the video while still playing the audio - it displays "No HDMI Link" on the LED, and then stops.
So, OK - maybe there is a problem with your TV's DVI connector - have you tried or can you try another device connected to your TV's DVI connection? An HD satellite or cable box, or even a DVD player with DVI or HDMI output? If you connect another device to your TV's DVI connection and have fade outs, then it's your TV. If it plays fine, then the HD DVD player has a problem.