HDCP wont work with an analog connection. If you want hdcp (drm) then you need to use a digital connection dvi or hdmi.
But you should be able to watch blu-rays over an analog connection without hdcp. Atleast according to spec. But then again Cyberlink dosent even follow the specs. PowerDVD even downsamples non protected audio.
My ATI 4850 and cat 8.10 works fine on my system with a digital connection (with HDCP). Plays blu-rays.
Try WinDVD 9 Trial. Should be able to play blu-rays with that atleast.
AMP: Hegel H100, DAC: Arcam rDAC, Speakers: Tannoy Revolution Signature DC6T, TV: LG 55EF950V, HTPC: Intel Skylake i5-6500