After unpacking the plug-in installation package, you unlock the dlls from it.
By default, Windows blocks the installation of DLLs that it could not verify security.
This occurs with CHM extension help files.
Note: The Unblock button (or the checkbox) does not always is available. If it is not available, it is already Unlocked
Open AutoCAD and NETLOAD or APPLOAD again.
Still it did not work?
Do you have all the files in the folder? Check
Follow the procedure Load From Network