Today I got an error while running yum update command:

[root@lenovo ~]# yum update

[...]useless output[...]

 You could try using --skip-broken to work around the problem
** Found 1 pre-existing rpmdb problem(s), 'yum check' output follows:
5:ibm-print-npgpws-2.1-26.i386 is a duplicate with 5:ibm-print-npgpws-2.1-23.i386

This is not so hard and can be achieved with the following commands:

1. Check if maybe the last update process was not interrupted and you do not have some unfinished transations:

[root@lenovo ~]# yum-complete-transaction
Loaded plugins: ibm-check-lotus-updates, ibm-check-xorg-updates, ibm-repository, refresh-packagekit, versionlock
No unfinished transactions left.

List duplicate packages:

[root@lenovo ~]# package-cleanup --dupes
Loaded plugins: ibm-check-lotus-updates, ibm-check-xorg-updates, ibm-repository, refresh-packagekit, versionlock
ibm-print-npgpws-2.1-26.i386
ibm-print-npgpws-2.1-23.i386

Uninstall the duplicate package:

[root@lenovo ~]# package-cleanup --cleandupes
Loaded plugins: ibm-check-lotus-updates, ibm-check-xorg-updates, ibm-repository, refresh-packagekit, versionlock
--> Running transaction check
---> Package ibm-print-npgpws.i386 5:2.1-23 will be erased
--> Finished Dependency Resolution

Dependencies Resolved

====================================================================================================
 Package               Arch                   Version             Repository                 Size
====================================================================================================
Removing:
 ibm-print-npgpws      i386                  5:2.1-23            @el63/$releasever          279 k

Transaction Summary
====================================================================================================
Remove        1 Package(s)

Installed size: 279 k
Is this ok [y/N]: y
Downloading Packages:
Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
  Erasing    : 5:ibm-print-npgpws-2.1-23.i386                                                   1/1 
  Verifying  : 5:ibm-print-npgpws-2.1-23.i386                                                   1/1 

Removed:
  ibm-print-npgpws.i386 5:2.1-23                                                                                                                                                                                          

Complete!
[root@lenovo ~]#

Problem fixed!