[intelli]

Nachtrag:

Adobe say's these types of errors are generally due to permissions, locked files and/or licensing. Did you perhaps have CS3 installed? If so, run the CS3 clean script and see if there was anything left behind. Did you deactivate the previous version first (left over license files will cause problems later). Here are some other ideas:

Run Installer as Administrator
Uninstall everything Adobe with Revouninstaller (link (http://download.cnet.com/Revo-Uninst...-10687648.html)) then run CCleaner (registry) after reboot.
Did you properly remove license from previous CS?
Do you have Kaspersky installed? Even turned off it will block access to many system directory's and files.
Did you look at the installer logs (many hints in there)?
Create new user and try install again (if it works Profile may be corrupt).

intelli