[Yum] update problems

[G V]

Hi,
I am trying to do a yum update and get the following.

Resolving Dependencies
--> Populating transaction set with selected packages. Please wait.
---> Package libpcap.i386 14:0.8.3-9.RHEL4 set to be updated
---> Package centos-yumconf.noarch 0:4-4.2 set to be updated
---> Package tcpdump.i386 14:3.8.2-9.RHEL4 set to be updated
---> Package spamassassin.i386 0:3.0.1-0.EL4 set to be updated
---> Package php-pear.i386 0:4.3.9-3.6 set to be updated
---> Package php-mysql.i386 0:4.3.9-3.6 set to be updated
---> Package php.i386 0:4.3.9-3.6 set to be updated
---> Package php-ldap.i386 0:4.3.9-3.6 set to be updated
--> Running transaction check
--> Processing Dependency: perl(Net::DNS) for package: spamassassin
--> Processing Dependency: perl(Time::HiRes) for package: spamassassin
--> Processing Dependency: perl-Mail-SpamAssassin = 3.0.2-1 for
package: spamassassin-tools
--> Restarting Dependency Resolution with new changes.
--> Populating transaction set with selected packages. Please wait.
---> Package perl-Net-DNS.i386 0:0.48-1 set to be updated
---> Package perl-Time-HiRes.i386 0:1.55-3 set to be updated
--> Running transaction check
--> Processing Dependency: perl(Digest::HMAC_MD5) for package: perl-Net-DNS
--> Processing Dependency: perl-Mail-SpamAssassin = 3.0.2-1 for
package: spamassassin-tools
--> Restarting Dependency Resolution with new changes.
--> Populating transaction set with selected packages. Please wait.
---> Package perl-Digest-HMAC.noarch 0:1.01-13 set to be updated
--> Running transaction check
--> Processing Dependency: perl-Mail-SpamAssassin = 3.0.2-1 for
package: spamassassin-tools
--> Finished Dependency Resolution
Error: Missing Dependency: perl-Mail-SpamAssassin = 3.0.2-1 is needed
by package spamassassin-tools

Not sure what the problem is. Any ideas/help would be much appreciated.
George