I think Rick wants you to loginto their account - to see if you have an issues logging in as they do.
I have this same difficulty -- or had -- when I upgraded from 6.4.4 to 7.4.1. Quite a few of my users couldn't login with the same results as you noted. Clearing cache and blowing away cookies helped some of them but not all. Funny, but some of the ones having problems - their problems disappeared after the third or fourth try.
I've had no problem logging into their accounts, so I know it is not the system and it is a small percentage of users having the problem.
