This could work for you:
I'm not sure why but there is a glitch with their system for some users/browsers. When I log onto erslist I first have to log in my username and password, and then, when it tells me its failed to log in, I will hit refresh and all of a sudden I'm in and its working.
Its funny - there's a glitch for me when I have to sign into Perb as well as I have to sign in 2x to get on. The first time I sign in it tells me I failed to log in - I do the same thing a 2nd time then I'm in.
Erslist and Perb are the only two sites I've ever had these weird glitches. I can't explain why it happens.