company-clang-arguments errors when opening file and company-clang not working

[jade2k11598]

Hi,
So I'm in the process of following instructions to setting up C++ IDE found in http://tuhdo.github.io/c-ide.html. I'm at the part of setting up the company-mode with clang (http://tuhdo.github.io/c-ide.html#orgheadline15). Followed all the setups, including the setup of the .dir-locals.el placed at the project root, which has the following content:
((nil . ((company-clang-arguments . ("-I/Users/jade/spdlog/include/")))))

But every time I try to open a file I get this error:

The local variables list in /Users/jade/spdlog/
contains values that may not be safe (*).

Do you want to apply it?  You can type
y  -- to apply the local variables list.
n  -- to ignore the local variables list.
!  -- to apply the local variables list, and permanently mark these
      values (*) as safe (in the future, they will be set automatically.)

  * company-clang-arguments : ("-I/Users/jade/spdlog/include/")

I enter y to get pass this point, but every time I attempt to trigger the company completion to include a header file found in the include path set above, it fails to recognize any headers found in that subdirectory (e.g. I just get a message "No completion found"). For instance in that include path, there is a spdlog subdirectory which contain numerous header files. Even after typing:

#include "spdlog/

followed with trigger the key that triggers company-complete, emacs prompts "No completion found".

I know I have the desired key for company-complete setup correctly, because I have also setup the company-c-headers feature and it has no problem finding the various system headers in the path setup for company-c-headers, when triggering the same company-complete key. But it never succeeds finding headers found in the path setup for company-clang-arguments. I suspect that the error I get when I first open up any file in that project, is a hint that somehow there's something wrong in my setup, but I'm not that familiar with trouble-shooting emacs lisp.

Here's what is in my init.el file as far as setting up company related stuff:

(require 'company)
(add-hook 'after-init-hook 'global-company-mode)
(setq company-backends (delete 'company-semantic company-backends))
(define-key c-mode-map  (kbd "C-<tab>") 'company-complete)
(define-key c++-mode-map (kbd "C-<tab>") 'company-complete)

(eval-after-load 'company
  '(add-to-list
    'company-backends 'company-c-headers)
  )

(setq company-c-headers-path-system '("/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/"
                                      "/usr/local/include/"))

Any help would be greatly appreciated.