Hi Victor. I'm right in the middle of something now- just saw your post. Rather than explaining in detail here, I can send you an example of how I do a login system with our databases. It works very well.
It involves creating a master login, one record file with a few globals; and another one, or perhaps two user files, depending on how you prefer to set it up. Then the privileges for each specific database are set in the user file. Creating a relationship from the master login to the user file (master::USERPASSWORD = user::USERPASSWORD) then enables user access privileges for each user.
Let me know if you are interested, and I can send them to you fully open and you can check the scripting of the system.
Manny Silva
Child and Family Services
New Bedford, MA
MannyRSilva@hotmail.com