so DCS is only starting in 2D for you, no matter what? you can always try going into your DCS \ bin (via command line), and then try: dcs.exe --force_enable_VR
Not sure what you're asking though. the .dll you asked about, you have in the correct dir
Edit: I'll look in a bit, but there's probably a setting somewhere in the DCS GUI to force VR. (honestly, I haven't flown pancake in so long, I need to look. It's probably right in front of my face within the menu's)
Edit: look under the VR tab (of the options), to see if you have "enable virtual reality headset" still checked (sorry, just a stab...)