Joshua, this is an informational message, not a bug. Each time you add a new attribute (field) to an entity (table), these changes also need to be made to your database structure.
When you run the application from the modeler it compares the current database structure with the one defined in the model, and if new attributes have been added or removed you get this dialog asking to synchronize the database to the model. Simply click the 'Synchronize database' button and the changes should be made to your database for you.
Could you look at the following question:
Try to change your DPI setting.
Ok Thanks I am sorted now. The only thing is you have to end the program via task manager when you get this message. There is no cancel or ok option.
The problem with the disappearing buttons because of a different DPI setting will be fixed in version 2.5.2.