error uploading images and media

Hi,
I have wordpress 3.6 and twenty thirteen theme. My issue is uploading media or images. I want to set a featured image, in this example called “simple-hummus” (a recipe).

“simple-hummus.png” has failed to upload due to an error
The uploaded file could not be moved to wp-content/uploads/2013/08.

What I already tried:
• I already set me permission to 755.
• I created, via ftp, a wp-content folder, an uploads folder, a 2013 folder, and a 08 folder.
• my image size is way below 100mb.

Any suggestions would be great. Thank you.