yum update failure - package not installed - rpm says it is there?

Hi all,
  I have a new install of FC6 X86_64.  In trying a yum update I continually arrive at this point of failure:
  --> Running transaction check
  --> Processing Dependency: php = 5.1.6-3 for package: php-pdo
  --> Finished Dependency Resolution
  Error: Missing Dependency: php = 5.1.6-3 is needed by package php-pdo

rpm -qa : | grep php reports that php-5.1.6-3 is installed.  I have considered reinstalling php-5.1.6-3 with --force but since rpm already thinks it is there I cant see that this will do any good.

Ideas?  Can I erase the rpm database and then rebuild it?  I have already run rpm --rebuilddb.

Thanks,


Bob