I've been trying to install iRedMail, but am getting dependency errors.

All I can find on searches says that most people with these errors are not running a supported OS, but I'm on CentOS 5.3 which is supported.

The out put of the errors is

php-imap-5.1.6-27.el5.i386 from base has depsolving problems
  --> Missing Dependency: php-common = 5.1.6-27.el5 is needed by package php-imap-5.1.6-27.el5.i386 (base)
clamd-0.94.2-1.el5.rf.i386 from iRedMail has depsolving problems
  --> Missing Dependency: clamav = 0.94.2-1.el5.rf is needed by package clamd-0.94.2-1.el5.rf.i386 (iRedMail)
php-mbstring-5.1.6-27.el5.i386 from base has depsolving problems
  --> Missing Dependency: php-common = 5.1.6-27.el5 is needed by package php-mbstring-5.1.6-27.el5.i386 (base)
clamd-0.94.2-1.el5.rf.i386 from iRedMail has depsolving problems
  --> Missing Dependency: libclamunrar.so.5 is needed by package clamd-0.94.2-1.el5.rf.i386 (iRedMail)
clamd-0.94.2-1.el5.rf.i386 from iRedMail has depsolving problems
  --> Missing Dependency: libclamav.so.5 is needed by package clamd-0.94.2-1.el5.rf.i386 (iRedMail)
clamd-0.94.2-1.el5.rf.i386 from iRedMail has depsolving problems
  --> Missing Dependency: libclamunrar_iface.so.5 is needed by package clamd-0.94.2-1.el5.rf.i386 (iRedMail)
1:php-eaccelerator-0.9.5.2-2.el5.i386 from epel has depsolving problems
  --> Missing Dependency: php-zend-abi = 20050922 is needed by package 1:php-eaccelerator-0.9.5.2-2.el5.i386 (epel)
php-ldap-5.1.6-27.el5.i386 from base has depsolving problems
  --> Missing Dependency: php-common = 5.1.6-27.el5 is needed by package php-ldap-5.1.6-27.el5.i386 (base)
clamd-0.94.2-1.el5.rf.i386 from iRedMail has depsolving problems
  --> Missing Dependency: libclamav.so.5(CLAMAV_PUBLIC) is needed by package clamd-0.94.2-1.el5.rf.i386 (iRedMail)
clamd-0.94.2-1.el5.rf.i386 from iRedMail has depsolving problems
  --> Missing Dependency: libclamav.so.5(CLAMAV_PRIVATE) is needed by package clamd-0.94.2-1.el5.rf.i386 (iRedMail)
Error: Missing Dependency: php-common = 5.1.6-27.el5 is needed by package php-imap-5.1.6-27.el5.i386 (base)
Error: Missing Dependency: php-common = 5.1.6-27.el5 is needed by package php-ldap-5.1.6-27.el5.i386 (base)
Error: Missing Dependency: libclamav.so.5 is needed by package clamd-0.94.2-1.el5.rf.i386 (iRedMail)
Error: Missing Dependency: php-common = 5.1.6-27.el5 is needed by package php-mbstring-5.1.6-27.el5.i386 (base)
Error: Missing Dependency: libclamav.so.5(CLAMAV_PUBLIC) is needed by package clamd-0.94.2-1.el5.rf.i386 (iRedMail)
Error: Missing Dependency: libclamav.so.5(CLAMAV_PRIVATE) is needed by package clamd-0.94.2-1.el5.rf.i386 (iRedMail)
Error: Missing Dependency: libclamunrar_iface.so.5 is needed by package clamd-0.94.2-1.el5.rf.i386 (iRedMail)
Error: Missing Dependency: clamav = 0.94.2-1.el5.rf is needed by package clamd-0.94.2-1.el5.rf.i386 (iRedMail)
Error: Missing Dependency: php-zend-abi = 20050922 is needed by package 1:php-eaccelerator-0.9.5.2-2.el5.i386 (epel)
Error: Missing Dependency: libclamunrar.so.5 is needed by package clamd-0.94.2-1.el5.rf.i386 (iRedMail)
You could try using --skip-broken to work around the problem
You could try running: package-cleanup --problems
                        package-cleanup --dupes
                        rpm -Va --nofiles --nodigest
The program package-cleanup is found in the yum-utils package.
Installation failed, please check the terminal output.