[CentOS] Missing dependencies

I tried to update my Centos with yum update as I have done in the past, 
but this time I received a list of dependencies.  This is a new 
experience for me and I would appreciate any help/suggestions.  Here is 
one of the lines:

Error: Missing Dependency: php = 4.3.9-3.15 is needed by package php-mysql

Todd

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