Installing ojs. error of not exist/not writable directory issue

while clicking on the link “install open journal system” at the very beginning, i got an error “The directory specified for uploaded files does not exist or is not writable.” and “The public files directory does not exist or is not writable.” i have created one directory named files (not web accessible) and even set permission to 0777 but this error still pops up. what can i do to solve this issue.

What are the settings in config.inc.php, I mean what are the paths you have given for the two folders?