Ok, just as a controlled experiment, I decided to attempt to actually download and install the iTunes 10.6.3.25 manual installer from the apple website. I chose to do this on my Toshiba laptop running Windows Vista 32 bit Home Premium because I barely, if ever, utilize this laptop to run iTunes - and I figured if something did go drastically wrong, I could simply use the system restore feature to return the OS to the time previous to the attempt. Just as a reminder, the laptop was exhibiting the exact same behavior as my windows 7 64 bit Desktop(I.e. iTunes version 10.6.1.7 installed with Apple Software Date Tool not working as weak as the iTunes help>check for download finding the new version but being unable to proceed any farther - basically the same boat everyone seems to be in). I had seem a fair amount of people for which the manual download/install process worked sufficiently.
Anyway, I downloaded the 32 bit Windows iTunes 10.6.3.25 installer(the only one offered since Apple sensed I was downloading to a 32 bit windows OS). I made sure to right click on the installer file once downloaded and run the file as an Administrator. The process took much longer than I expected and I got quite worried during it as the installer seemed to be performing the same processes (i.e. validation, copying, removing, updating registration, etc...) over and over again. I was , at a time, worried that the installer was stuck in some type of vicious loop that it would be endlessly trapped inside. Finally, success! A screen appeared stating iTunes had been successfully installed and I had to do a restart. I was afraid that my songs/apps/movies/playlists/etc... would be lost or need to be reimported, but this was not the case. When I opened iTunes everything was exactly as I had left it with all my data exactly in the same place. My apple ID was running upon opening and the iTunes store was easily reachable. All iTunes functionality I have tested(so far) seems AOk. And the iTunes version correctly shows as 10.6.3.25...nice. The major thing I was afraid of, however, did occur - that being the new iTunes version install did NOTHING to change the situation with the clearly broken Apple Software Update tool. This tool is still performing exactly as it did prior to the 10.6.3.25 install. So it looks to me, at this point that Apple may have been tinkering with iTunes over the past 2 to 3 days to get it up to snuff, but the Apple Software Tool needs to be addressed by Apple.