Error installing Panda Internet Security 2008

I recently re-installed my Windows Vista 64-bit system, but when I try to
re-install my Panda Internet Security 2008, it displays an error on the
installation screen which says:
Feature Transfer Error
Feature: NT
Component: ResidenteFicherosNTPAV
File: C:\Windows\SysWOW64\PAV
Error: Access is denied

This did not happen on my last Vista installation which was also 64-bit, and
I was wondering what is going on? I am the administrator of this computer and
I should have access to install this, I don't understand, and light on this
would be nicely appreciated.
Thanks