Yesterday I ran into an issue with installing Adobe 8.0 on a user's computer which was running Windows XP SP2. The installation error was 1406, access is denied. It pointed to certain keys in the registry which the installation program could not write to.
After checking the permissions on the registry keys that the error pointed to, I found out that the I was not set as the owner on these keys.
After changing the permissions on the registry keys (changing ownership), the program installation continued without a hitch.
Please note that to get the details on how to change the registry key permissions please refer to the Adobe forum that talks about the error 1406.