compiz.real crashed with SIGSEGV

Binary package hint: compiz

I was trying to use the update manager and the crash happened and I got the following error on
the update manager

Could not download all repository indexes

The repository may no longer be available or could not be contacted because of network problems. If available an older version of the failed index will be used. Otherwise the repository will be ignored. Check your network connection and ensure the repository address in the preferences is correct.

Also there is a message on the box as follows

GPG error: http://packages.medibuntu.org intrepid Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 2EBC26B60C5A2783Failed to fetch http://www.getautomatix.com/apt/dists/dapper/main/binary-i386/Packages.gz 404 Not Found
Some index files failed to download, they have been ignored, or old ones used instead.

ProblemType: Crash
Architecture: i386
CrashCounter: 1
DistroRelease: Ubuntu 8.10
ExecutablePath: /usr/bin/compiz.real
NonfreeKernelModules: ath_hal
Package: compiz-core 1:0.7.8-0ubuntu2
ProcAttrCurrent: unconfined
ProcCmdline: /usr/bin/compiz.real --ignore-desktop-hints --replace --indirect-rendering core ccp
ProcEnviron:
 PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games
 LANG=en_US.UTF-8
 SHELL=/bin/bash
Signal: 11
SourcePackage: compiz
Stacktrace: #0 0x08055c0c in ?? ()
StacktraceTop: ?? ()
ThreadStacktrace:

Title: compiz.real crashed with SIGSEGV
Uname: Linux 2.6.27-7-generic i686
UserGroups: adm admin cdrom dialout lpadmin plugdev sambashare