VS.NET installation fails

[Andrea]

I have been using VS.net. But now i am unable to install VS.net to another
machine. When i try to install visual studio.net, i am getting an error
message "unable to load sitsetup.dll" . I cannot proceed installing because
of this error. The error appears as soon as I start installing the
Prerequisites CD - sitsetup.dll is normally present on the Prerequisites CD
(antivirus and firewall are disabled).
The OS is windows XP home edition sp2 installed.

Hope someone can help me
Andrea