Login Error

I have been using Word Press for a few months now. I am currently using v2.0. I have taken a recent break from it recently, now I am no longer able to login to the admin interface. I have tried all of the passwords I use for sites and all it does is reload the page once I hit submit. However, Firefox display the following error.

document.loginform has no properties line 10 of wp-login.php

I am not able to login as an admin, however all other uses have no problems logging in. What is going on?