Comment 2 for bug 821443

Same issues here.

If I remembered well, this appears after these packages updated:

Commit Log for Sat Aug 6 12:36:08 2011

Upgraded the following packages:
app-install-data (0.11.10.1) to 0.11.10.2
bamfdaemon (0.2.92-0ubuntu1) to 0.2.94-0ubuntu1
binutils (2.21.52.20110707-1ubuntu1) to 2.21.53.20110805-1ubuntu1
binutils-dev (2.21.52.20110707-1ubuntu1) to 2.21.53.20110805-1ubuntu1
cups (1.4.7-1ubuntu5) to 1.4.8-2
cups-bsd (1.4.7-1ubuntu5) to 1.4.8-2
cups-client (1.4.7-1ubuntu5) to 1.4.8-2
cups-common (1.4.7-1ubuntu5) to 1.4.8-2
cups-ppdc (1.4.7-1ubuntu5) to 1.4.8-2
empathy (3.1.4-1ubuntu2) to 3.1.4-1ubuntu3
empathy-common (3.1.4-1ubuntu2) to 3.1.4-1ubuntu3
evolution (3.1.4-0ubuntu1) to 3.1.4-0ubuntu2
evolution-common (3.1.4-0ubuntu1) to 3.1.4-0ubuntu2
evolution-data-server (3.1.4-0ubuntu4) to 3.1.4-0ubuntu5
evolution-data-server-common (3.1.4-0ubuntu4) to 3.1.4-0ubuntu5
evolution-plugins (3.1.4-0ubuntu1) to 3.1.4-0ubuntu2
firefox (6.0~b3+build2+nobinonly-0ubuntu1) to 6.0~b4+build1+nobinonly-0ubuntu1
firefox-gnome-support (6.0~b3+build2+nobinonly-0ubuntu1) to 6.0~b4+build1+nobinonly-0ubuntu1
firefox-locale-en (6.0~b3+build2+nobinonly-0ubuntu1) to 6.0~b4+build1+nobinonly-0ubuntu1
firefox-locale-ja (6.0~b3+build2+nobinonly-0ubuntu1) to 6.0~b4+build1+nobinonly-0ubuntu1
ghostscript (9.04~dfsg~20110801-0ubuntu1) to 9.04~dfsg-0ubuntu1
ghostscript-cups (9.04~dfsg~20110801-0ubuntu1) to 9.04~dfsg-0ubuntu1
ghostscript-x (9.04~dfsg~20110801-0ubuntu1) to 9.04~dfsg-0ubuntu1
gir1.2-gtk-3.0 (3.1.10-0ubuntu1) to 3.1.10-0ubuntu2
gir1.2-polkit-1.0 (0.101-4) to 0.102-1
gnome-session (3.1.3-0ubuntu6) to 3.1.3-0ubuntu7
gnome-session-bin (3.1.3-0ubuntu6) to 3.1.3-0ubuntu7
gnome-session-common (3.1.3-0ubuntu6) to 3.1.3-0ubuntu7
gnome-session-fallback (3.1.3-0ubuntu6) to 3.1.3-0ubuntu7
gtk-3-examples (3.1.10-0ubuntu1) to 3.1.10-0ubuntu2
indicator-messages (0.4.92-0ubuntu3) to 0.4.92-0ubuntu4
indicator-messages-gtk2 (0.4.92-0ubuntu3) to 0.4.92-0ubuntu4
indicator-status-provider-mc5 (0.4.92-0ubuntu3) to 0.4.92-0ubuntu4
libass4 (0.9.12-1) to 0.9.13-1
libbamf0 (0.2.92-0ubuntu1) to 0.2.94-0ubuntu1
libbamf3-0 (0.2.92-0ubuntu1) to 0.2.94-0ubuntu1
libcamel-1.2-28 (3.1.4-0ubuntu4) to 3.1.4-0ubuntu5
libcups2 (1.4.7-1ubuntu5) to 1.4.8-2
libcupscgi1 (1.4.7-1ubuntu5) to 1.4.8-2
libcupsdriver1 (1.4.7-1ubuntu5) to 1.4.8-2
libcupsimage2 (1.4.7-1ubuntu5) to 1.4.8-2
libcupsmime1 (1.4.7-1ubuntu5) to 1.4.8-2
libcupsppdc1 (1.4.7-1ubuntu5) to 1.4.8-2
libebackend-1.2-1 (3.1.4-0ubuntu4) to 3.1.4-0ubuntu5
libebook1.2-11 (3.1.4-0ubuntu4) to 3.1.4-0ubuntu5
libecal1.2-9 (3.1.4-0ubuntu4) to 3.1.4-0ubuntu5
libecal1.2-dev (3.1.4-0ubuntu4) to 3.1.4-0ubuntu5
libedata-book-1.2-10 (3.1.4-0ubuntu4) to 3.1.4-0ubuntu5
libedata-cal-1.2-12 (3.1.4-0ubuntu4) to 3.1.4-0ubuntu5
libedataserver1.2-14 (3.1.4-0ubuntu4) to 3.1.4-0ubuntu5
libedataserver1.2-dev (3.1.4-0ubuntu4) to 3.1.4-0ubuntu5
libedataserverui-3.0-1 (3.1.4-0ubuntu4) to 3.1.4-0ubuntu5
libevolution (3.1.4-0ubuntu1) to 3.1.4-0ubuntu2
libgail-3-0 (3.1.10-0ubuntu1) to 3.1.10-0ubuntu2
libgail-3-common (3.1.10-0ubuntu1) to 3.1.10-0ubuntu2
libglew1.5 (1.5.7.is.1.5.2-1ubuntu3) to 1.5.7.is.1.5.2-1ubuntu4
libglew1.5-dev (1.5.7.is.1.5.2-1ubuntu3) to 1.5.7.is.1.5.2-1ubuntu4
libglewmx1.5 (1.5.7.is.1.5.2-1ubuntu3) to 1.5.7.is.1.5.2-1ubuntu4
libglewmx1.5-dev (1.5.7.is.1.5.2-1ubuntu3) to 1.5.7.is.1.5.2-1ubuntu4
libgs9 (9.04~dfsg~20110801-0ubuntu1) to 9.04~dfsg-0ubuntu1
libgs9-common (9.04~dfsg~20110801-0ubuntu1) to 9.04~dfsg-0ubuntu1
libgtk-3-0 (3.1.10-0ubuntu1) to 3.1.10-0ubuntu2
libgtk-3-bin (3.1.10-0ubuntu1) to 3.1.10-0ubuntu2
libgtk-3-common (3.1.10-0ubuntu1) to 3.1.10-0ubuntu2
libgtk-3-dev (3.1.10-0ubuntu1) to 3.1.10-0ubuntu2
libgtk-3-doc (3.1.10-0ubuntu1) to 3.1.10-0ubuntu2
libindicator-messages-status-provider1 (0.4.92-0ubuntu3) to 0.4.92-0ubuntu4
libmodplug1 (1:0.8.8.2-3) to 1:0.8.8.2-3ubuntu1
libmono-addins-gui0.2-cil (0.6.1-1ubuntu1) to 0.6.1-2ubuntu1
libmono-addins0.2-cil (0.6.1-1ubuntu1) to 0.6.1-2ubuntu1
libpolkit-agent-1-0 (0.101-4) to 0.102-1
libpolkit-agent-1-dev (0.101-4) to 0.102-1
libpolkit-backend-1-0 (0.101-4) to 0.102-1
libpolkit-gobject-1-0 (0.101-4) to 0.102-1
libpolkit-gobject-1-dev (0.101-4) to 0.102-1
libunity-core-4.0-4 (4.6.0-0ubuntu1) to 4.6.0-0ubuntu2
libunity-core-4.0-dev (4.6.0-0ubuntu1) to 4.6.0-0ubuntu2
libvlc5 (1.1.11-2) to 1.1.11-2build1
libvlccore4 (1.1.11-2) to 1.1.11-2build1
marlin (0.1-0~464~oneiric1) to 0.1-0~466~oneiric1
policykit-1 (0.101-4) to 0.102-1
ubuntu-minimal (1.235) to 1.236
ubuntu-standard (1.235) to 1.236
unity (4.6.0-0ubuntu1) to 4.6.0-0ubuntu2
unity-common (4.6.0-0ubuntu1) to 4.6.0-0ubuntu2
unity-services (4.6.0-0ubuntu1) to 4.6.0-0ubuntu2
update-manager (1:0.152.9) to 1:0.152.10
update-manager-core (1:0.152.9) to 1:0.152.10
vlc (1.1.11-2) to 1.1.11-2build1
vlc-data (1.1.11-2) to 1.1.11-2build1
vlc-nox (1.1.11-2) to 1.1.11-2build1
vlc-plugin-notify (1.1.11-2) to 1.1.11-2build1
vlc-plugin-pulse (1.1.11-2) to 1.1.11-2build1

Installed the following packages:
libmatroska4 (1.2.0-1)
libx264-116 (2:0.116.2037+gitf8ebd4a-1ubuntu1)