I have this exact same problem. I have an LG BP-125 BluRay player. I have two different external USB hard drives, both 1TB, and BOTH formatted to NTFS; one is a WD, the other a Toshiba. The Toshiba 1TB is immediately recognized by the BluRay player, and I'm able to navigate the files and play them (in several different file formats: MP4, MKV, AVI). The WD drive is NOT recognized by the player; the player acts as if nothing is plugged into the USB port. (Both drives work perfectly on my laptop connection.)
I have NO CLUE as to why the WD drive would not be recognized. It can't be the formatting, because both are NTFS-formatted. (I would not have a problem with FAT32 formatting in any case, because all of my files are under 4GB, but Windows does not offer an option to format either of these drives as FAT32 due to their size.)