Bit hard to explain via forums but here goes..
What version kernel modules do you have ?
rpm -qa kmod*
I'll assume there _42.0.8.EL
Which version kernel are you running?
uname -r
I'll assume it's 2.6.9-42.0.10.EL
I'll also assume it's a production machine so we will downgrade the kernel.
If you can sit in front of the machine, reboot it and select a 2.6.9-42.0.8.EL kernel at boot time.
Or edit /boot/grub/grub.conf and change the 'default' line to be your required kernel. The list of kernels start at 0 and count down the list. Save your edits and reboot.
Repeat the above commands and make sure your kmods equal your kernel.
Now, remove the 'newer' kernels.
yum remove kernel-2.6.9-42.0.10.EL
yum remove kernel-smp-2.6.9-42.0.10.EL
If it wants to remove anything else come back here with a list.
Now try the update process again.