This error has been explained in many threads already. You need to copy subTsgMSCD16.dll and subTsgMSCD32.dll from your plugins directory to ePSXe's main directory.
As far as the "Games don't work" comment, you're going to have to be more precise before we can offer possible solutions. How do they not work? What games don't work? Your configurations (especially for your GPU) would be very helpful.