Backup Manager gives Warning: Permission denied.

[slv]

Hello
I've got problem with Backup Manager.
When I click a link [Backup Manager] at Tools & Settings page this redirects me:

:8443/smb/settings/tools-proxy?url=/admin/backup&returnAction=tools
-->
:8443/smb/redirect/pleskin?dst=%2Fadmin%2Fbackup&src=%2Fsmb%2Fsettings%2Ftools&srcController=Smb_SettingsController
-->
:8443/admin/backup
-->
:8443/admin/
-->
:8443/admin/home
-->
:8443/smb/

and at the end I'm receiving message:
Warning: Permission denied.

I've not found any problems in logs.

Could you help me to find solution?

PS:
My plesk version is 12.0.18 Update #26 on CentOs 6