I am consistently getting this error message. Now I'm new to this emulator thing, and just trying to get my laptop into deployment shape. Am I loading my iso wrong, or is there something I'm not doing correctly. I am running windows 10 and have downloaded numerous emulators only to have the same thing happen.
You can also select CDVDnull as plugin since pcsx2 doesn't need one for ISOs unless you want to play from the physical game disk in your DVD drive.
I still recommend to create an ISO file of your your game disk since this prevents loading lags.