Installing issue

I keep getting denied while trying to install this app, I’ve tried numerous of times with different admin privileges. no luck.

This is exactly what I get after trying to install:
( I’ve tried creating the folder directly on our FTP, but doesn’t work)

Installing Plugin: Background Manager 1.2.2

Downloading install package from http://downloads.wp.xz.cn/plugin/background-manager.1.2.2.zip…

Unpacking the package…

Installing the plugin…

Could not create directory. /public_html/theskateboardmag.com/wp-content/plugins/background-manager/

Plugin install failed.

Return to Plugin Installer

http://ww.wp.xz.cn/extend/plugins/background-manager/