I'm having the same issue ^^;
I've never set a character password prior to this,
If I try to type in the password I can't get any further then 6 characters, but if I manually click the on-screen keyboard I can enter in a longer password. However the 'Password must have at least 6 characters' box comes up no matter how long the password is.
Using Windows 7, if that has any effect on the issue.