Solution to "An error occurred during the installation..."

[Ken]

So, if you are having a problem reinstalling office 2007 (the installer
crashes right after entering your key number) here is how you fix the problem.

Start…Run…Regedit

Navigate to
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Office\Delivery\SourceEngine\Downloads
delete the following keys:
{30120000-0011-0000-0000-0000000FF1CE}-C
{30120000-0015-0409-0000-0000000FF1CE}-C
{30120000-0016-0409-0000-0000000FF1CE}-C
{30120000-0018-0409-0000-0000000FF1CE}-C
{30120000-0019-0409-0000-0000000FF1CE}-C
{30120000-001A-0409-0000-0000000FF1CE}-C
{30120000-001B-0409-0000-0000000FF1CE}-C
{30120000-0044-0409-0000-0000000FF1CE}-C
{30120000-006E-0409-0000-0000000FF1CE}-C

Each of the GUIDs above correspond to a different office 2007 app, and
office 2007 itself.

Here is why you could not reinstall: The error was being caused by the LIS
(local installation sources) not being where the registry said they should
be. The actual error (HResult: 0x80070002) means that the installer could
not find the files. If you delete the references to them in the registry
then the installer will not look for cached copies in the LIS during
installation and you will be able to push through with no problems.

Seems like the installer will glitch from time to time and leave these
entries behind even after a clean install. When the files from MSOcache are
removed by the installer and you try to reinstall, the installer is trying to
load the cached files it thinks exists. Because they do not exist, the
installer throws an exception:

“Catalyst execution finished: 06/01/2006 19:49:58. Return code: 0.
Exception caught: HResultOnly.†And you get the friendly “An error occurred
during the installation and Microsoft Office Professional Plus 2007 (Beta)
setup was unable to complete.†Error message.

Hope this helps someone.