Check the log QHST to see if there were repeated login attempts. If you find the disable message, do a help on it for further information. Depending on how your security settings are it may disable the profile and even the device after a certain number of invalid log in attempts. Another place I have seen this happen is when people have a macro set up to log them in. Not a good idea security wise. If they password changes and they do not change the macro, this will cause invalid login attempts as well. It could be a number of reasons with different sources trying to connect to the DB2 databases as well. Things like web pages, web services, data imports into office documents all need a valid built in login. If that changed the it breaks.