I have come to the same conclusion that if we want to play BD media we might need to get specialised software, and that costs.
I don't know when you got this LG drive or if it came with the computer but I get the feeling that it was a year or two ago, and that PowerDVD was pe-installed on the system. Same here. But I don't know if my PowerDVD software ever worked with BD media as I never tested it. I also get the impression that this is the first time you have used this drive to try and play BD movies.
My error in a previous post. I said LG computer but I see where you said LG drive. So if this is an OEM system and is recently acquired, then a visit to the computer maker's web site might help.
But in the end, if your PowerDVD 8 fails to play this BD media for any reason then there is little you can do.