I was starting an SBS 2003 to SBS 2011 Migration for a customer today and it failed the SBS 2003 SP1 check! So – I downloaded the relevant components and installed the ones that had not been installed. All fine and dandy, apart from when I got to KB891193 where it failed with Fatal errors repeatedly.
Scouring the web for solutions was pretty fruitless – suggestions of removing the Fax Service (make sure you have SBS 2003 CD1 handy) and running the update as Domain Administrator (which I was) proved fruitless.
I finally decided to try and remove the Client Apps which refused to comply, so as a last resort I felt that it might benefit from a reinstallation of the Client Apps part of SBS 2003 installation (make sure you have SBS 2003 CD3 handy!)
After what seemed like an eternity where nothing was happening, the reinstallation completed, the server rebooted and then I tried KB891193 again and it instantly installed without a single complaint.
So – after 8 hours of wasted time – I can now continue with my SBS 2011 installation! Roll on the weekend.