title: I'm having trouble installing CMake -- For some reason it says it can't create a folder
body: <p>So here's the thing -- I'm trying to install CMake (and the installation was almost complete too) but then it showed this message:</p>
  
  <p>CMake Error at cmake_install.cmake:36 (file):
    file cannot create directory: /usr/local/doc/cmake-3.7.  Maybe need
    administrative privileges.</p>
  
  <p>Screen shot:
  since stack overflow won't let me post images, here's a link:
  <a href="https://s13.postimg.org/8vygwqiwn/Screenshot_from_2016_11_04_17_39_11.png" rel="nofollow noreferrer">https://s13.postimg.org/8vygwqiwn/Screenshot_from_2016_11_04_17_39_11.png</a></p>
  
  <p>But the thing is, I am the admin. Does anyone know what that problem is?</p>