Does this error occur when you try to download the installation file, or when you try to install a file that you've downloaded.

At what point in the process does the message occur, and what specifically does it say.

My experience has been a couple registry keys associated with Quicktime are the culprits.

Val

First, be sure to uninstall Quicktime/Itunes.

In registry editor, doe a search for Quicktime, delete any and all keys with this identifier.

If a key does not delete, try to take ownership of it.
Right click on the key, select Permissions. Press the Advanced button, then the Owners tab of the dialog that pops up. Hightlight your login, prss the Apply button.

If this works, you can then delete the key.

Note: In my case, something was really, really hosed with three or four QT keys, to the point that I ended up wiping the machine and reinstalling. It had a few other problems as well, which may or may not have been related.

If you are not experienced or comfortable with the registry, get someone who is. And be sure to create a restore point before trying this.

Val

I'm not quite sure I know what you mean by "reinstall registry".

You could try going back to earlier restore points, before you tried to do the iTunes update - might work.

While researching this problem, several others seemed to have similar problems and no good solution was ever mentioned.

It may be that some of us just get caught in the Apple - MS crossfire. And don't have the Kevlar body armor. Sigh.

Val

I believe I did try a separate install of QT, it failed as well.

I brought up permissions on the keys as part of my effort to delete the offending buggers, which, in the course of events, I was never able to change or delete. Not no way, no how.

Val

I'm out of ideas, hope someone else can jump in here.

Val