I am using IE as well, but I just bought a new HP computer with the XP Home Media edition and when I tried the method laid out by everyone 13 times, it never worked. I received an email this morning from WV folks and they repeated the same steps as laid out a few messages up. I was kind of frustrated.
Then I decided to take one last shot, but wanted to make sure I tried something different. I went to my Advanced Settings and there was a box NOT checked called "Use HTTP 1.1 through proxy settings"
I checked this box, closed out of the security center and now the Vault works! I may be over-reading the value of this box being checked, but it seems to have helped in my situation.
Thanks to all for the help!