I have the same problem. Instead, I'm using both Sony products. Using 32'' Bravia s-series and a dvd player. when switching the video output to HDMI 1 there's no video no sound. Do you think the HDMI cable i use play a big factor on this one. The cable i bought was very cheap compared to other products.
Make sure that you have connected the HDMI cable to the port labelled HDMI on the side of your Monitor and on the HDMI out port of you DVD player. Normally you must select the proper channel for your DVD player.
At least have you seen the DVD player menu displayed on screen?