error on shut down

I continually receive this error message at shut down.

Attempted to 'check the setting of /proc/sys/kernel/yama/ptrace_scope' also as root and system did not recognize my root 'su' password.
text of error message below.

polkit-gnome-authentication-agent-1-bugreport.txt

System: Linux 2.6.35-29-generic #51-Ubuntu SMP Fri Apr 15 17:12:35 UTC 2011 x86_64
X Vendor: The X.Org Foundation
X Vendor Release: 11001000
Selinux: No
Accessibility: Disabled
GTK+ Theme: Crux
Icon Theme: gnome
GTK+ Modules: gnomesegvhandler, canberra-gtk-module

Memory status: size: 233160704 vsize: 233160704 resident: 7151616 share: 5685248 rss: 7151616 rss_rlim: 18446744073709551615
CPU usage: start_time: 1305588264 rtime: 2 utime: 2 stime: 0 cutime:0 cstime: 0 timeout: 0 it_real_value: 0 frequency: 100

----------- .xsession-errors ---------------------
** (gnome-session:1479): DEBUG: GsmClient: disposing /org/gnome/SessionManager/Client7
** (gnome-session:1479): DEBUG: GsmXSMPClient: xsmp_finalize (0x1b9ab40 [pulseaudio 1016091834930dcb14130558827319566800000014790036])
** (gnome-session:1479): DEBUG: GsmAutostartApp: (pid:1589) done (status:0)
** (gnome-session:1479): DEBUG: GsmDBusClient: obj_path=/org/freedesktop/DBus interface=org.freedesktop.DBus method=NameOwnerChanged
** (gnome-session:1479): DEBUG: GsmDBusClient: obj_path=/org/freedesktop/DBus interface=org.freedesktop.DBus method=NameOwnerChanged
** (gnome-session:1479): DEBUG: GsmDBusClient: obj_path=/org/freedesktop/DBus interface=org.freedesktop.DBus method=NameOwnerChanged
** (gnome-session:1479): DEBUG: GsmDBusClient: obj_path=/org/freedesktop/DBus interface=org.freedesktop.DBus method=NameOwnerChanged
** (gnome-session:1479): DEBUG: GsmDBusClient: obj_path=/org/freedesktop/DBus interface=org.freedesktop.DBus method=NameOwnerChanged
** (gnome-session:1479): DEBUG: GsmDBusClient: obj_path=/org/freedesktop/DBus interface=org.freedesktop.DBus method=NameOwnerChanged
Could not attach to process. If your uid matches the uid of the target
process, check the setting of /proc/sys/kernel/yama/ptrace_scope, or try
again as the root user. For more details, see /etc/sysctl.d/10-ptrace.conf
ptrace: Operation not permitted.
/home/robertd/1602: No such file or directory.
No stack.
--------------------------------------------------