Could not create directory

You are using Ubuntu package for WordPress right? Had you tried conventional install (just downloading official WP archive and setting it up with LAMP)?

While it’s not very “Linux way” maybe, it’s commonly suggested to stick with that for WordPress. I briefly dealt with Ubuntu WP package in the past and ended up doing just that as well.

PS if that 3.8.2 stands for WP version it’s not current either.