Help!! Audio issues in dolby digital

[tracy]

I need some technical help! I'm pulling my hair out here! I just purchased a Sony Blu-ray and while the picture is fabulous I am having audio issues with sound cutting out during playback of blu-ray discs only and only while attemping to play back using dolby digital surround through my Sony STR-DE875 receiver (optical hook-up - Dolby Digital and DTS capable). I've contacted Sony they advised that I set DRC to MAX on the player which does not resolve the issue (also set it to max on receiver). No problems when playing back using uncompressed option on blu-ray dvd's or when using Downmix PCM instead of Dolby Digital, cutting out occurs only when playing back using Dolby Digital and only with Blu-ray discs, other dvds play fine using DD. I'm ready to return it but as a newbie I'm not sure if this is a compression issue, a settings issue or a problem with the player. Any suggestions will be happily accepted! Is Downmix PCM better than Dolby Digital?