BD/HD-DVD Playback Windows XP Pro 64 Bit

[DougieB]

Hi
I run Win XP Pro 64 as my main OS (I also run on sepparate HDDs Win XP Pro 32 and Win 7 RC1 64Bit). I have a problem with playback on Win XP 64 bit,
I use Cyberlink 7.3 Ultra with the upgrade patch from Cyberlink and it runs fine for BD and HD-DVD on both Win XP 32 and Win 7 64 but will not playback on Win XP 64. My PC:
AMD Athlon 64x2 7750 BE@3.1Ghz
Biostar TA780G M2+ Mobo
8 Gb Corsair XMS2 PC 6400 DDR2 Ram
Radeon 4670 512Mb DDR3 (Catalyst 9.6)
160 Gb Samsung HDD (Win XP 64)
500 Gb WD HDD (Win & 64)
80 Gb Hitachi HDD (Win XP 32)
LG GGC H20L BD/HD-DVD Multi drive

Has anyone using Win XP 64 come across this problem and, if so, did they find a solution. I would like to continue using Win XP 64 as my main OS
with BD etc playback rather than have to reboot everytime I want to view a movie.
Any help on this greatly appreciated.

DougieB