The path specified by InstallLocation in HidMapperSettings is not supposed to point directly to the folder of the executable but rather to the installation folder of the game (or the “root” folder if you like).
ISE attempts to detect this installation folder at startup by reading information from the Windows registry which is created by applications when they’re installed. This folder is also verified to contain the appropriate executable (which is NOT located directly under this folder but rather in a sub folder).
Where is your ED:H installation located?