I ended up doing something really weird to my DNN installation.  I was using the latest version of the User Account module along with DNN 4.5.1 and set up a "State" field in the registration.  I set the default value to my state, and included a validation string.  I then required a valid profile for login and registration.  On my admin and host accounts I already had the state property set to a valid state.  However, when I try to login with any account, a critical error occurrs - the validation string for the state property is apparently invalid.  So even though I've got a valid state entered in the state property, the validation string is invalid and it causes the login to fail.  Of all the irony...  Anyway, has anyone encountered this before?  What can be done without redoing the entire site?  Where are the validation strings stored?

Exactly what I needed - somehow I had truncated my validation string.  Thanks!