Ok... I've encountered another problewm..

As soon as I try to log in this message appears:
"UNABLE to authenticate. Please check your login/password or create a new account. error700"
Hm, ok, so I try to create a new account and it says:
"Unable to create account. This user already exists"
This undoubtedly means that I've been typing the wrong password for the login, since the "account" already exists... But I haven't, lol, I've been inserting the right password all along and I cannot still log in, please, help me.. ???