I agree with zest on the digital audio setting - it must be bitstream to give you Dolby Digital and DTS outputs. PCM is purely a downmixed stereo. Subce Miscanthus already has the DVD player connected directly to the TV, though, the 990's out of the picture already on the HDMI. If the TV has a DVI input, it would be unable to get an audio signal. If the TV has an HDMI input there may be a setting on the TV doing something, but the player really ought to have some way to play nice with DVI displays.

The issue is with what your TV is doing with the audio carried over the HDMI cable. What kind of input does the TV have - DVI or HDMI?