Errno::EACCES in PostsController#create when uploading images with refile

I was following a guide on how to use Refile and it's multiple image uploading functionality and ran into a permission error when the application tries to upload the images to another local folder.

The gems I've used are refile and mini_magick.

Errno::EACCES in PostsController#create
Permission denied @ unlink_internal - E:/projects/photoblog-with-refile-gem/tmp/uploads/cache/

I've tried changing the permissions and restarting the server with no luck

chown -R 777 E:/projects/photoblog-with-refile-gem/tmp/

I've also tried changing the permission from 777 to 666, again no luck.