This system has been running for several months without any problems. This problem just started happening after the system died due to a power outage.
I do have apparmor running on the system.
I found the following error in the syslog
Feb 20 10:08:58 svr-ml1 kernel: [ 3254.615880] amavisd[29699]: segfault at 5d63000 ip 00007fecd99ea324 sp 00007ffff50c2958 error 4 in libc-2.11.1.so[7fecd9963000+17a000]
Here are the entries from the zimbra.log when the amavis service starts.
Feb 20 10:08:55 svr-ml1 zimbramon[1130]: 1130:info: Starting antispam via zmcontrol
Feb 20 10:08:56 svr-ml1 amavis[6476]: Ignoring stale PID file /opt/zimbra/log/amavisd.pid, older than system uptime 0 0:01:00
Feb 20 10:08:56 svr-ml1 amavis[6476]: starting. /opt/zimbra/amavisd/sbin/amavisd at svr-ml1.ogc.orangegrove.org amavisd-new-2.6.4 (20090625), Unicode aware, LC_ALL="C", LANG="C"
Feb 20 10:08:56 svr-ml1 amavis[6476]: user=1001, EUID: 1001 (1001); group=, EGID: 1001 4 5 1001 1002 (1001 4 5 1001 1002)
Feb 20 10:08:56 svr-ml1 amavis[6476]: Perl version 5.010001
Feb 20 10:08:57 svr-ml1 amavis[6476]: SpamControl: init_pre_chroot on SpamAssassin done
Feb 20 10:08:57 svr-ml1 amavis[6494]: Net::Server: Process Backgrounded
Feb 20 10:08:57 svr-ml1 amavis[6494]: Net::Server: 2011/02/20-10:08:57 Amavis (type Net::Server::PreForkSimple) starting! pid(6494)
Feb 20 10:08:57 svr-ml1 amavis[6494]: Net::Server: Binding to UNIX socket file /opt/zimbra/data/amavisd/amavisd.sock using SOCK_STREAM
Feb 20 10:08:57 svr-ml1 amavis[6494]: Net::Server: Binding to TCP port 10024 on host 127.0.0.1
Feb 20 10:08:57 svr-ml1 amavis[6494]: Net::Server: Group Not Defined. Defaulting to EGID '1001 4 5 1001 1002'
Feb 20 10:08:57 svr-ml1 amavis[6494]: Net::Server: User Not Defined. Defaulting to EUID '1001'
Feb 20 10:08:57 svr-ml1 amavis[6494]: Module Amavis::Conf 2.207
Feb 20 10:08:57 svr-ml1 amavis[6494]: Module Archive::Zip 1.30
Feb 20 10:08:57 svr-ml1 amavis[6494]: Module Compress::Zlib 2.024
Feb 20 10:08:57 svr-ml1 amavis[6494]: Module Convert::TNEF 0.17
Feb 20 10:08:57 svr-ml1 amavis[6494]: Module Convert::UUlib 1.33
Feb 20 10:08:57 svr-ml1 amavis[6494]: Module Crypt::OpenSSL::RSA 0.26
Feb 20 10:08:57 svr-ml1 amavis[6494]: Module DBD::mysql 4.013
Feb 20 10:08:57 svr-ml1 amavis[6494]: Module DBI 1.609
Feb 20 10:08:57 svr-ml1 amavis[6494]: Module DB_File 1.82
Feb 20 10:08:57 svr-ml1 amavis[6494]: Module Digest::MD5 2.39
Feb 20 10:08:57 svr-ml1 amavis[6494]: Module Digest::SHA 5.48
Feb 20 10:08:57 svr-ml1 amavis[6494]: Module IO::Socket::INET6 2.59
Feb 20 10:08:57 svr-ml1 amavis[6494]: Module MIME::Entity 5.427
Feb 20 10:08:57 svr-ml1 amavis[6494]: Module MIME::Parser 5.427
Feb 20 10:08:57 svr-ml1 amavis[6494]: Module MIME::Tools 5.427
Feb 20 10:08:57 svr-ml1 amavis[6494]: Module Mail:

KIM::Signer 0.37
Feb 20 10:08:57 svr-ml1 amavis[6494]: Module Mail:

KIM::Verifier 0.37
Feb 20 10:08:57 svr-ml1 amavis[6494]: Module Mail::Header 2.06
Feb 20 10:08:57 svr-ml1 amavis[6494]: Module Mail::Internet 2.06
Feb 20 10:08:57 svr-ml1 amavis[6494]: Module Mail::SPF v2.007
Feb 20 10:08:57 svr-ml1 amavis[6494]: Module Mail::SpamAssassin 3.003001
Feb 20 10:08:57 svr-ml1 amavis[6494]: Module Net:

NS 0.66
Feb 20 10:08:57 svr-ml1 amavis[6494]: Module Net::LDAP 0.40
Feb 20 10:08:57 svr-ml1 amavis[6494]: Module Net::Server 0.97
Feb 20 10:08:57 svr-ml1 amavis[6494]: Module NetAddr::IP 4.027
Feb 20 10:08:57 svr-ml1 amavis[6494]: Module Socket6 0.23
Feb 20 10:08:57 svr-ml1 amavis[6494]: Module Time::HiRes 1.9721
Feb 20 10:08:57 svr-ml1 amavis[6494]: Module URI 1.53
Feb 20 10:08:57 svr-ml1 amavis[6494]: Module Unix::Syslog 1.1
Feb 20 10:08:57 svr-ml1 amavis[6494]: Amavis:

B code NOT loaded
Feb 20 10:08:57 svr-ml1 amavis[6494]: Amavis::Cache code NOT loaded
Feb 20 10:08:57 svr-ml1 amavis[6494]: SQL base code NOT loaded
Feb 20 10:08:57 svr-ml1 amavis[6494]: SQL::Log code NOT loaded
Feb 20 10:08:57 svr-ml1 amavis[6494]: SQL::Quarantine NOT loaded
Feb 20 10:08:57 svr-ml1 amavis[6494]: Lookup::SQL code NOT loaded
Feb 20 10:08:57 svr-ml1 amavis[6494]: Lookup::LDAP code loaded
Feb 20 10:08:57 svr-ml1 amavis[6494]: AM.PDP-in proto code loaded
Feb 20 10:08:57 svr-ml1 amavis[6494]: SMTP-in proto code loaded
Feb 20 10:08:57 svr-ml1 amavis[6494]: Courier proto code NOT loaded
Feb 20 10:08:57 svr-ml1 amavis[6494]: SMTP-out proto code loaded
Feb 20 10:08:57 svr-ml1 amavis[6494]: Pipe-out proto code NOT loaded
Feb 20 10:08:57 svr-ml1 amavis[6494]: BSMTP-out proto code NOT loaded
Feb 20 10:08:57 svr-ml1 amavis[6494]: Local-out proto code loaded
Feb 20 10:08:57 svr-ml1 amavis[6494]: OS_Fingerprint code NOT loaded
Feb 20 10:08:57 svr-ml1 amavis[6494]: ANTI-VIRUS code loaded
Feb 20 10:08:57 svr-ml1 amavis[6494]: ANTI-SPAM code loaded
Feb 20 10:08:57 svr-ml1 amavis[6494]: ANTI-SPAM-EXT code NOT loaded
Feb 20 10:08:57 svr-ml1 amavis[6494]: ANTI-SPAM-C code NOT loaded
Feb 20 10:08:57 svr-ml1 amavis[6494]: ANTI-SPAM-SA code loaded
Feb 20 10:08:57 svr-ml1 amavis[6494]: Unpackers code loaded
Feb 20 10:08:57 svr-ml1 amavis[6494]: DKIM code loaded
Feb 20 10:08:57 svr-ml1 amavis[6494]: Tools code NOT loaded
Feb 20 10:08:57 svr-ml1 amavis[6494]: Found $file at /usr/bin/file
Feb 20 10:08:57 svr-ml1 amavis[6494]: No $altermime, not using it
Feb 20 10:08:57 svr-ml1 amavis[6494]: Internal decoder for .mail
Feb 20 10:08:57 svr-ml1 amavis[6494]: Internal decoder for .asc
Feb 20 10:08:57 svr-ml1 amavis[6494]: Internal decoder for .uue
Feb 20 10:08:57 svr-ml1 amavis[6494]: Internal decoder for .hqx
Feb 20 10:08:57 svr-ml1 amavis[6494]: Internal decoder for .ync
Feb 20 10:08:57 svr-ml1 amavis[6494]: No decoder for .F tried: unfreeze, freeze -d, melt, fcat
Feb 20 10:08:57 svr-ml1 amavis[6494]: Found decoder for .Z at /bin/uncompress
Feb 20 10:08:57 svr-ml1 amavis[6494]: Found decoder for .gz at /bin/gzip -d
Feb 20 10:08:57 svr-ml1 amavis[6494]: Found decoder for .bz2 at /bin/bzip2 -d
Feb 20 10:08:57 svr-ml1 amavis[6494]: No decoder for .lzo tried: lzop -d
Feb 20 10:08:57 svr-ml1 amavis[6494]: No decoder for .rpm tried: rpm2cpio.pl, rpm2cpio
Feb 20 10:08:57 svr-ml1 amavis[6494]: Found decoder for .cpio at /bin/cpio
Feb 20 10:08:57 svr-ml1 amavis[6494]: Found decoder for .tar at /bin/cpio
Feb 20 10:08:57 svr-ml1 amavis[6494]: No decoder for .deb tried: ar
Feb 20 10:08:57 svr-ml1 amavis[6494]: Internal decoder for .zip
Feb 20 10:08:57 svr-ml1 amavis[6494]: No decoder for .7z tried: 7zr, 7za, 7z
Feb 20 10:08:57 svr-ml1 amavis[6494]: No decoder for .rar tried: rar, unrar
Feb 20 10:08:57 svr-ml1 amavis[6494]: No decoder for .arj tried: arj, unarj
Feb 20 10:08:57 svr-ml1 amavis[6494]: No decoder for .arc tried: nomarch, arc
Feb 20 10:08:57 svr-ml1 amavis[6494]: No decoder for .zoo tried: zoo, unzoo
Feb 20 10:08:57 svr-ml1 amavis[6494]: No decoder for .lha tried: lha
Feb 20 10:08:57 svr-ml1 amavis[6494]: No decoder for .cab tried: cabextract
Feb 20 10:08:57 svr-ml1 amavis[6494]: No decoder for .tnef tried: tnef
Feb 20 10:08:57 svr-ml1 amavis[6494]: Internal decoder for .tnef
Feb 20 10:08:57 svr-ml1 amavis[6494]: No decoder for .exe tried: rar, unrar; lha; arj, unarj
Feb 20 10:08:57 svr-ml1 amavis[6494]: Using primary internal av scanner code for ClamAV-clamd
Feb 20 10:08:57 svr-ml1 amavis[6494]: Found secondary av scanner ClamAV-clamscan at /usr/bin/clamscan
Feb 20 10:08:57 svr-ml1 amavis[6494]: initializing Mail::SpamAssassin
Feb 20 10:08:58 svr-ml1 zimbramon[1130]: 1130:info: Starting antivirus via zmcontrol
Thanks for your help
Richard