Can't address why this isn't working but some side notes:
You should have gotten Boot Camp to update itself to 3.3 in a couple steps.
With 8GB RAM and laptop, you have 4-8GB page space, 8GB hibernation, 20GB devoted to Windows core, 10GB for SP1 and other updates as temp space, 3-5GB temp/tmp/cache, and whatever you need for applications.
20 + 8 + 4 + 10 + 4 + 4 (apps) = 50GB, so it does fit.
SP1 was/is only 1GB or less but it unzip, writes temp files, prepares the installer, makes the updates, and won't function with less than 9GB free space.
Keep everything extraneous disconnected.
I use MSSE but sometimes security suites can supposedly get in the way of an installer and need more permission or change of rule in say Kaspersky KIS 2012.
The trouble with stopping is: do you restore to last system check point? do you do safe boot? do you run chkdsk to be sure there are no fragments or errors?
I tried to see if there were pre-requisite libraries or applications, or this is a full installer? And of course Windows 8 has its own build branch of tools I suppose? The links just take me to yours, and then at the bottom:
http://go.microsoft.com/fwlink/?LinkId=245233