WordPress 3.8 update error!

I am experiencing the following error message when trying to update: Warning: copy(/homepages/18/d335365933/htdocs/app335365949/wp-admin/includes/update-core.php): failed to open stream: Permission denied in /homepages/18/d335365933/htdocs/app335365949/wp-admin/includes/class-wp-filesystem-direct.php on line 200

I then try to manually update. Unpack the zip file and all that shows up are a lot of .php files that I have no clue what to do with. I have Dreamweaver but have never used it. Please help. Thank you!