@rijnton I don't know if putting a Path variable up under User Variables works!? What has been suggested is editing the Path variable in the box BELOW, under "System Variables". If you try that (adding a semicolon then C:\Program Files\Common Files\Arcsoft\Bin) take care not to mess-up any of the existing Path values already there!
If that doesn't work then suspect you have hit the same wall as TruckChase!, and hopefully he will find the secret to getting your installs to work. Sounds like he has done everything including the regsvr32 bit with, what is it, ASAudioHD.ax. Not sure madshi wants to help w/Arcsoft but I wish you good luck.
EDIT: I see TC! was advising exact Path instructions whilst I typed here...