I had an issue getting Office 2007 to Install this morning.
In the end it turned out it would not install because i had the following installed:
Office 2003 Web Components
Expression Web Designer beta 1.
Once i got rid of them it installed fine.
This is probably not the cause of your issue, as i did not have a problem uninstalling the Beta 2 TR version....but still quite anoying all the same.