next_tab and prev_tab keybindings stop working if changed

When I'm trying to change the default keybindings for "Switch to the next tab" and "Switch to previous tab" (next_tab and prev_tab), new bindings don't work. When I open "Preferences" dialog again, it says that keybindings for this actions are "Disabled". Restoring default values doesn't help either, they're still "Disabled". In the config file I have corresponding records:

[global_config]
[keybindings]
  next_tab = <Primary>Page_Down
  prev_tab = <Primary>Page_Up

[user@xennie terminator #292]$ apt-cache policy terminator
terminator:
  Installed: 0.96-0ubuntu1
  Candidate: 0.96-0ubuntu1
  Version table:
 *** 0.96-0ubuntu1 0
        500 http://ru.archive.ubuntu.com/ubuntu/ precise/universe amd64 Packages
        100 /var/lib/dpkg/status

[user@xennie terminator #295]$ lsb_release -rd
Description: Ubuntu precise (development branch)
Release: 12.04

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: terminator 0.96-0ubuntu1
ProcVersionSignature: Ubuntu 3.2.0-21.34-generic 3.2.13
Uname: Linux 3.2.0-21-generic x86_64
ApportVersion: 2.0-0ubuntu4
Architecture: amd64
Date: Thu Apr 5 12:39:09 2012
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Release amd64 (20111012)
PackageArchitecture: all
ProcEnviron:
 TERM=xterm
 PATH=(custom, username)
 LANG=en_US.UTF-8
 SHELL=/usr/bin/zsh
SourcePackage: terminator
UpgradeStatus: Upgraded to precise on 2012-03-31 (4 days ago)