mkinitrd command failed with error: "No module mptscsi found for kernel"

Issue

• While creating a new initial ramdisk image, mkinitrd command failed with following error messages.

# mkinitrd -v -f /boot/initrd-2.6.18-348.16.1.el5.img 2.6.18-348.16.1.el5
Creating initramfs
Modulefile is /etc/modprobe.conf
[..]
Looking for deps of module mptscsi
No module mptscsi found for kernel 2.6.18-348.16.1.el5, aborting.           

• Why kernel module mptscsi is missing in RHEL-5 kernel packages ?

# uname -a
Linux host1 2.6.18-194.el5 #1 SMP Tue Mar 16 21:52:39 EDT 2010 x86_64 x86_64 x86_64 GNU/Linux

# modprobe mptscsi
FATAL: Module mptscsi not found.