"ERROR: SetGenericOption() Error: The device is not ready."
indicates that the user does not have sufficient WRITE rights to the .INI file.
You might consider placing the ini files in common folders which are configured to allow a WRITE access to all users. Leaving the ini files in the default location or in the same folder as the Ranger DLL or OCX, may be feasible as well as long as the WRITE access permission is enabled.