CS5.5 upgrade won't install on window vista studio?

I bought a cs5.5 design standard upgrade for my cs3 design standard. I bought it and download what i need to install it. When I go try to install it tells me its missing a file and not enough memory to do it and need to make room. I have enough room for this software and i download everything. I'm getting very fustrated with it. What is the problem, what do i need to do and how can i get this problem fix?