It's possible that you have a setting wrong in either the receiver or blu-ray player.
The lossless audio formats can be passed via HDMI to a receiver that has the capability to decode the signal.
The only other option, that I know of for sure, is to have the blu-ray player decode the signal and sent it to the receiver via individual RCA analog cables. Not all blu-ray players have analog outputs for every channel, mine doesn't.
I don't know if it's possible to send a decoded signal via HDMI or not, but I'd suspect that it's possible.