You will need to add the pex files. The psc files are just your source code and can be opened in a text editor (I edit mine in Notepad++). The pex files are the compiled executables, and what works in the game. If you have a look in the script directory, and then in the source directory, there should be a corresponding psc for every pex that was supplied with the vanilla game (assuming you let the installer unzip the source files). You can take the psc away and the game works fine, but if you take the pex away then the quest scripts and so on won't function. As an asides, don't feel too bad about it, I completely left out the pex and psc of one of my first mods. Thank you.