I have recently installed RHEL 4 Update 6 with MSA Attached. When It got rebooted it is displaying error:
All it is stucking at this point.
Any Idea? How to solve the issue.

I have No Hands Wetted Ever in GRUB/ Single User mode..So Do provide the overall Steps if possible.

If you installed it on the same computer that has all those other Linux OSs in your profile, you can reinstall grub from a live session using the Ubuntu CD.
Boot into a live session with Ubuntu CD and run command from terminal: sudo fdisk -l to show us what your drives contain, post the output here please.
And if it is the same computer as the rest, which /boot/grub/menu.lst were you using prior to installing RHEL?
If you are not sure, it probably was the last Linux you installed, of which you should post the /boot/grub/menu.lst file so someone can show you how to add RHEL to it, look for a /boot/grub/menu.lst in all of the Linux for one of these files that contains entries for all of them if you're not sure.
Then someone can show how to reinstall Grub to the MBR of the first drive set to boot in the bios. If you have more than one drive, specify which is the one set to boot first also.