There is an error in the login or in the password you wrote. You should try to write again.
You tried to create the database where your queries and your preferences are saved, but this database was already created.
This error can happen when you try to create a new query or preference. Because there is no connection between the software and the database, you can't create anything new. The best things to do is to log yourself out, then reconnect yourself to the database.
You're unable to create a new query or preference, because the database where they will be saved doesn't exist. The best way to remove this error is to create the UserPerso database with the "Options" menu or with Ctrl+Alt+C.
The query you tried to execute has one or more error. You should check the syntax of the query and do the required correction. Or you can also try another query.
You probably used the "OK" button before selecting any qyery/preference to edit/delete. Select one before clicking.
You can't show a previous result before having already executed a query. The last result is reseted each time you close the software.
You tried to log out while you weren't actually loged. Go back to the login page and connect yourself to the database.