i got a terratec aureon 5.1 pci also with the c-media chip on board.
my sys is an x86 64bit Windows 7 core 2 quad
tried 3 days to activate the spdif .. also tried your hints about the striker card...
nothing worked always teh system freeze if i ttried to start the soft from the tray
now i found this page cmediadrivers - Google Code
it's for all cards with the c-media 8738/8768 chipset!!
installed it and now i don't need the soft becaus spdif is activated and you can also playback dts/dolby bitstream!!!! WOW
... was hard work 4 me to find a solution ..
but you guys showed me the direction