Unable to access ACP because of Authentication issue

I seem unable to access my ACP because whenever I retype my password to access the ACP, the session id changes itself, so I am caught in an endless loop of re-authenticating myself as the session ID changes.
I have tried clearing my browser cache, cookies, and rebooting my computer, but they don't remedy the problem. I am using Firefox 2.0.0.14 (at time of posting).

Thank you,
Cuine