I have this problem when I am inserting the password field in to the database table. the password is stored in a encripted format and is not allowing the user to get in with the password.
You just need to do the same process to the password that the user enters the second time and then compair the result of that with the one stored in the database - you shouldnt have to decrypt any password. If they forget the password, then create a new random one for them.