You can post the full commandline, if you want, but I'm quite sure that I found the problem:
The include dirs get quoted (because of the spaces), but the last character is a backslash (when added via the dialog) and so it escapes the last quote of the include-statement. I think we should remove it (the last backslash) to avoid such misbehaviour, or use forward-slashes instead, gcc accepts them, but I think on windows we should use the native path-seperators.
You can try if that's the cause, by manually removing the trailing backslashes.