SIL software installation failed at disk 5

Hi,
My SIL Software installer failed on disk 5, see my error message below.
I am not that techie and a friend told me about this website where experts might provide me help or a step by step procedure on how to resolve this problem.
Hope to hear from you soon.
Thanks in advance.

SIL Software Update Disk 5 Installation – Error
Could not successfully install Windows Installer 2.0.
The installation cannot continue.
