Is anyone else experiencing this problem?
Have you cleared the cookie? I know that you said that your browsers do not store cookies, but you should nonetheless check to see if it stored a Netbuilders cookie. Which browsers are you using? If you hare having problems with multiple browsers, then something really strange is going on.
The cookie was part of the problem. I have not had any problems since I cleared the cache and the cookie. My problem was isolated to FireFox. Perhaps the problem is due to the fact that you have cookies blocked. Try turning them on as see what happens. It is possible that cookies are required with the vBulletin upgrade.
"Democracy is two wolves and a lamb voting on what to have for lunch. Liberty is a well-armed lamb contesting the vote." -- Benjamin Franklin