I confused with the permission and user/group for folder www-data. exactly how the arrangements are suitable for the www-data user groups and for any additional users.

then I also had problems in the administrator page, the page list of Categories and Tags can not I see the list. when adding the tag / new categories also list immediately disappeared.
Then later when I did install new themes and plugins I do not get the right ftp user for use.

[b]sorry to bother, I need help.[/b]