I solved the blackout problems with a some adjustment to the TV setup. I had the TV setup at the highest being 1080p @60 H but i think my TV does not like this setting so set it one lower and the problem has gone away.
Would still like the solution to the audio problems ver 4.0.4. though.
I have 2 problems though they could be interconnected, not sure?
1. I upgraded to ver 4.0.4 on the MED400X and all the movie files play great, the backround sounds come through perfect but when people talk, etc that is stifled to a large degree and echo-ee. It is a similar problem to what Jere_530 reported on the 15th June 2011 in the forum. I have the device connected to the TV via the HDMI cable and the sound to a surround sound amp via 2 x RCA cables (left and right).
2. Due to this problem i reverted to ver 3.0.5 (using the beta version install first). Everything plays (picture and sound perfect) except now i experience a screen blackout/flicker for a very short period like a second or so but every 10 to 15 minutes throughout any movie that i play - it is intermittent in other words but happens with every movie i play.
I then reverted to ver 4.0.4 but the same thing happens as with ver 3.0.5. This never happened with the software version that i had on the device when i purchased it but only after i upgraded to the latest version and due to the audio problems experienced, going back to the earlier versions.