When I try to install I used to get the 1606 error but after doing a factory restore I was able to start the install and when it tries to copy the deploy files to my hard drive I get an error message saying unable to copy files to user appdata unable to use copy function. I turned off the Dep and even took ownership of the OS and it still cannot use the copy function. I am using disks i purchased in my college bookstore. I had a previous version installed but have not been able to locate any autocad registry files when I search.
You might right-click the setup.exe and run as Adminsitrator to see if you get any other results. Also, you might check here:
http://usa.autodesk.com/adsk/servlet/ps/dl/item?siteID=123112&id=9579121&linkID=9240817