Invalid Credentials - With correct login info

I simply cannot login. On the previous launcher, My login info worked just fine. Now for the MC 1.1 launcher pre-release, it simply gives me an error message saying "Invalid Credentials." I know for a fact that everything is typed out correctly, because I have the old launcher downloaded still and that one works just fine.

Steps to Reproduce:
I don't know how to make it happen. I haven't done anything, all I did was type in my login info, hit return, and then the error message appears.