There are unfinished transactions remaining. You might consider running yum-complete-transaction first to finish them

While updating my CentOS / RHEL HP Linux server via yum command it givens an error which read as follows:

There are unfinished transactions remaining. You might consider running yum-complete-transaction first to finish them

How do I fix this problem under RHEL / CentOS Linux 5.x server operating systems?

You will get this message only if yum finds incomplete or aborted yum transactions on a system.

Run yum-complete-transaction

Type the following command to finish transactions:
# yum-complete-transaction
I recommend running yum-complete-transaction --cleanup-only, which is safe option
# yum-complete-transaction --cleanup-only
The yum-complete-transaction command finds incomplete or aborted yum transactions on a system and attempts to complete them. It looks at the transaction-all and transaction-done files which can normally be found in /var/lib/yum if a yum transaction aborted in the middle of execution. If it finds more than one unfinished transaction it will attempt to complete the most recent one first. You can run it more than once to clean up all unfinished transactions.