I used to hit this periodically with my token in XI---chalked it up to weird timing with the token.

Double-check your caps lock and numbers lock settings. IDK how many times I've turned one of those on/off by mistake... makes you feel real stupid when you realize that was what was flubbing your password. I actually changed the registry key on my work laptop so numbers lock would be on during the Windows Log-in screen (it didn't have a number pad, so when people tried to put in a password, keys around K would put in numbers...so they couldn't log into it... heheh). If you're on a laptop without a number pad, this could very well be what is tripping you up--some have the number lock button in a bad place and it's easy to hit by mistake.

You say you've been resetting your password at "the site". Are you going directly to the SE AM site, or following the link from the email? The reason I'm asking is we've seen spoofed emails in the past fishing for login information. Just want to make sure you aren't possibly going to one such site, giving out information, and someone is erroneously trying to sign in (they don't have your token)--causing temporary lockouts on your account or something. Make sure you are changing your password at the official SE site by following a link from the lodestone or something like that.