Additional information:
The updates applied last night -
apr-util.i386                            0.9.4-22.el4_8.3       updates         
bind-libs.i386                           20:9.2.4-30.el4_8.6    updates         
bind-utils.i386                          20:9.2.4-30.el4_8.6    updates         
iptraf.i386                              3.0.0-1.2.el4.rfx      smeos           
krb5-libs.i386                           1.3.4-62.el4_8.3       updates         
openldap.i386                            2.2.13-12.el4_8.4      updates         
openldap-servers.i386                    2.2.13-12.el4_8.4      updates         
openssl.i686                             0.9.7a-43.17.el4_8.6   updates         
php.i386                                 4.3.9-3.31             updates         
php-domxml.i386                          4.3.9-3.31             updates         
php-gd.i386                              4.3.9-3.31             updates         
php-imap.i386                            4.3.9-3.31             updates         
php-ldap.i386                            4.3.9-3.31             updates         
php-mbstring.i386                        4.3.9-3.31             updates         
php-mysql.i386                           4.3.9-3.31             updates         
php-pear.i386                            4.3.9-3.31             updates         
Additional errors in the /var/log/messages:
Jan 19 10:00:09 s01 HORDE[28041]: [turba] DB Error: no such field: SELECT object_id, owner_id, 
object_type, object_members, object_uid, object_firstname, object_lastname, object_middlenames, 
object_nameprefix, object_namesuffix, object_alias, object_bday, object_spouse, 
object_anniversary, object_children, object_photo, object_phototype, object_homestreet, 
object_homepob, object_homecity, object_homeprovince, object_homepostalcode, object_homecountry, 
object_workstreet, object_workpob, object_workcity, object_workprovince, objec
Jan 19 10:00:01 s01 esmith::event[29579]: expanding /var/service/pop3s/peers/0
Jan 19 10:00:01 s01 esmith::event[29579]: ERROR: Cannot create output file //var/service/pop3s/peers/0.29584 Not a directory
Jan 19 10:00:01 s01 esmith::event[29579]:  at /etc/e-smith/events/actions/generic_template_expand line 56
Jan 19 10:00:01 s01 esmith::event[29579]: expanding /var/service/pop3s/peers/local
Jan 19 10:00:01 s01 esmith::event[29579]: ERROR: Cannot create output file //var/service/pop3s/peers/local.29584 Not a directory
Jan 19 10:00:01 s01 esmith::event[29579]:  at /etc/e-smith/events/actions/generic_template_expand line 56
Jan 19 10:00:01 s01 esmith::event[29579]: expanding /var/service/imaps/config
Jan 19 10:00:01 s01 esmith::event[29579]: expanding /var/service/imaps/peers/0
Jan 19 10:00:01 s01 esmith::event[29579]: expanding /var/service/imaps/peers/local
Jan 19 10:00:01 s01 esmith::event[29579]: expanding /var/service/pop3/peers/0
Jan 19 10:00:01 s01 esmith::event[29579]: ERROR: Cannot create output file //var/service/pop3/peers/0.29584 Not a directory
Jan 19 10:00:01 s01 esmith::event[29579]:  at /etc/e-smith/events/actions/generic_template_expand line 56
Jan 19 10:00:01 s01 esmith::event[29579]: expanding /var/service/pop3/peers/local
Jan 19 10:00:01 s01 esmith::event[29579]: ERROR: Cannot create output file //var/service/pop3/peers/local.29584 Not a directory
Jan 19 10:00:01 s01 esmith::event[29579]:  at /etc/e-smith/events/actions/generic_template_expand line 56
Numerous files in /var/log display as if they are 'directories' but are really only files owned by qpsmtp:clamav
[root@s01]# cd /var/log
[root@s01 log]# ls -l | grep clamav
drwxr-xr-x  2 clamav  clamav     4096 Oct 25 12:07 clamav
drwxr-s---  2 smelog  clamav     4096 Jan 18 21:33 freshclam
-rw-------  1 qpsmtpd clamav    28766 May  6  2010 ftp
-rw-------  1 qpsmtpd clamav       85 May 11  2010 iptables
-rw-------  1 qpsmtpd clamav     8231 May 17  2010 pop3
-rw-------  1 qpsmtpd clamav    65620 May 13  2010 pop3s
-rw-------  1 qpsmtpd clamav    28765 May 12  2010 smtp-auth-proxy
-rw-------  1 qpsmtpd clamav    12374 May 13  2010 spamd
On my desktop I installed Mozilla Thunderbird 3.1.7
It will configure and work as imaps:143 but fails when I try to configure it as pop:110
POP3 appears to be the main problem.