I'm sorry to hear that you're having some issues.
1. Does the 1080 content have the correct resolution, audio codec and video codec? Also, do you have enough bandwidth on your network?
2. Did you set "External Speakers" to ON in the Audio setup menu? You might also try a different optical cable to see if that's the issue.
I have some problems with my HTC5200.
Streaming 1080p content leads to stuttering, doing this with my LE40C630 will do fine.
Other problem is, that the optical input does not work for me.
I put the optical jack from my LE40C630 into the optical in an nothing happens.
Has someone clues for me?