What was the previous firmware version, and the current version loaded on the player?
Also, did you adjust the audio output settings? Sometimes they can revert with a firmware update is installed. Adjusting the audio menu options can often fix this.
Since I recently updated my BDP1500 firmware, it no longer plays movies in 5.1 surround sound.
I get surround fine with my cable TV channels. I am not sure what happened to the disc player.