FTP Credentials problem with upgrade

I backed up my files and database and ran the upgrade from 3.5.1 to 3.6. I clicked the blue “Update Now” button and WordPress happily downloaded the files, and ran the update scripts. I did a quick check of the site and it seemed like everything was okay. I next attempted to upgrade my ShareThis plugin. At this point the upgrade went very bad, and I decided to restore both my files and my database. That went fine, and the site is back to normal now.

When I go to run the upgrade again, however, I get a message that “To perform the requested action, WordPress needs to access your web server.” Along with boxes for my information. When I put that in, however, I get a notice that there is an error connecting to the server. I double checked my credentials, and even tested them successfully from a command line prompt. I can watch the FTP server console and see these transactions in realtime, and while I can see my login from the command prompt, I can’t see it when I run it from the WordPress browser window.

I’ve done a bit of googling and found the suggestions to add the ftp information to the wp-config.php file, but that doesn’t work either.

I’m flummoxed! Any and all suggestions would be greatly appreciated. I am on a windows 2008 server, and I have full access to it via RDP.
Thanks!