I've had the same issue as many others.. Error 1402 could not open key.. As has been mentioned, it's a permissions issue. My problem is on an Windows XP system. It always failed on the same key. So, get yourself a utility called "regmon" It's file that can monitor all access to the registry. Just google it and you can download it from Microsoft. No install required, just run an executable. Start the regmon utility and then start the installation. You can filter on the msiexec.exe that does the installation to reduce the amount of messages. When you get the error, stop the capture and look at the output of regmon. In my case it was complaining about being denied access to a particular key in the registry (HKEY_LOCAL_MACHINE\Software\Classes\ComCtl2.Animation.1\CLSID). When accessing the key It is running as the system user. I simply applied permissions to the key for the system and retried the install. It then proceeded and failed on another key. I then applied a permission for the system user to the whole HKEY_LOCAL_MACHINE\Software\Classes
** Backup your registry before doing this, just in case using system restore**
1. Open up the HKEY_LOCAL_MACHINE\Software\Classes
2. Rightclick and select permissions
3. In the Group or user names click on System
4. The Full Control and Read flags in the Permissions for SYSTEM window should be ticked
5. Click the Advanced button
6. Click on the System in the Permission entries
7. Tick the "replace permission entries on all child objects with entries shown here that apply to child objects"
8. Click Apply or OK.. It will take some time to ripple through.

Once done my install went through without a hitch..

I absolutely forgot about that little program. I've used it before and it is very helpful.
Thanks for posting a very good suggestion.