Audio problem
If you had another HDMI cable or HDMI source, then you could determine if the source, the cable, or the TV is the problem.
For an interim fix, you could use the Red/White RCA connections from the DVD player to the TV for audio and the HDMI for video. A digital optical or coax audio cable might also work depending on the available connections on your TV.
Monoprice has some inexpensive audio and HDMI cables that have worked well on my system.