More information. This seems to be a issue with the Admin page not being able to get to the Joomla feeds. I put the following line into my servers "hosts" file (c:\windows\system32\drivers\etc\hosts):
127.0.0.1 feeds.joomla.org
To purposely route the feeds link back to itself to see if this was the issue and the error message changed to:
PHP Notice: A feed could not be found at
http://feeds.joomla.org/JoomlaSecurityNews in D:\Inetpub\wwwroot\(mysite)\libraries\simplepie\simplepie.php on line 1520
So I'm thinking the fact that it can't get to the Feeds page is whats preventing the admin screen from working, which makes no sense....why would it "require" the feeds page. So I did more searching and found that the feeds server's IP address is 74.125.47.121 (currently at least...) and I update my host file and add a static route out our network onto the internet to get to this address.
The Admin page now works fine.
So for whatever reason the web server
HAS TO be able to get to feeds.joomla.org or you cannot login. This makes no sense and something needs to be changed to prevent this but I'm not good enough with PHP to tell you what to change. If you allow your web server to get to feeds.joomla.org it should work fine. What a PITA figuring this one out.
Edit: If enabling access to the feeds site isn't a option you can set your PHP error reporting down from all to all except notices like so:
error_reporting = E_ALL & ~E_NOTICE
This also gets you through this problem (and a bunch of others you may run into that arn't hard errors).