The patch to which *you* are referring, if you actually read the full note with it, is ONLY to be used if you had received the following message during the initial installation:
"A fatal error has occured during installation" after the message "AVControl SDK will be installed"
That, I repeat, is the ONLY circumstance in which you use that particular patch. And thus it is the only patch that requires a full uninstall of VS...
If you had also looked at the date of that patch (5 December 2007), you would also have realised that it was the most recent of the three fixes on the same page. And it is to the two earlier ones on the same page that DLA was referring. Moreover, they are general fixes/updates, rather than restricted to the very specific circumstances of the third 'hot fix'.
So go back to that page, and first download and install the bottom patch dated 6 November 2007. I repeat that you don't have to uninstall anything. Just install the patch over your existing installation of VS11.
Next, download and install the 'Hot Pack' dated 8 November 2007. That will upgrade your VS11+ to VS11.5+.
As for the one capture plug-in, that is another story entirely. Unfortunately, in their wisdom (and under the constraints of what Vista will or will not recognise), Corel dumped all the previous capture plug-ins which worked well in previous versions. They substituted it with the single InterVideo IVI plug-in you now have. Worse, it had unforseen limitations in the form of a bug which did not allow capture via firewire and using the DV format of analogue source material (which a lot of us use VS for, amongst other things). The 6 November patch fixes most of that bug, though sadly not all of it if you happen to have a Digital 8 camera playing analogue 8mm or Hi8 tapes.
Borrowing a well known phrase from Gomer Pyle USMC (the late, great, Jim Neighbors), For shame, for shame for shame.