Exchange SP1 fails with Error Code 1635

SP1 Upgrade makes it all the way to Hub Transport Role before failing with this error:
Summary: 6 item(s). 0 succeeded, 1 failed.
Elapsed time: 00:01:56
Hub Transport Role
Failed
Error:
Unable to remove product with code c3f10d8c-bd70-4516-b2b4-bf6901980741. This patch package could not be opened.  Verify that the patch package exists and that you can access it, or contact the application vendor to verify that this is a valid Windows Installer patch package. Error code is 1635.

This patch package could not be opened.  Verify that the patch package exists and that you can access it, or contact the application vendor to verify that this is a valid Windows Installer patch package
Elapsed Time: 00:01:56

I have tracked that Product code to: Microsoft Exchange 2007 Enterprise Anti-spam Filter Updates
The package DOES exist at C:\WINDOWS\Installer\563a44.msi

All of my AntiSpam within Exchange 2007 is disabled. The package it is complaining about appears to have been installed on 2007/06/11. I don;t know if that it Nov 6 or June 11.

My Anti Spam Updates are indeed updating through windows Updates, (even though I am not using them).
If I go to C:\WINDOWS\Installer\563a44.msi and dbl click it, I get the same error as above "This patch package could not be opened.  Verify that the patch package exists and that you can access it, or contact the application vendor to verify that this is a valid Windows Installer patch package"

I'm stuck.....

Thanks for any input you have.
Jason

BTW: This is a production server.