This window is shown when a feature you are trying to access is not available with your registration level.
Smart Diary Suite comes in several versions suited for different uses at different price levels to optimize the price-value ratio for each individual. Some people don't need all of the extensive features and thus shouldn't pay more for them!
If you are trying to access some feature that you need and you see this window, that means that your current registration level (determined by your registration key) does not have access to this particular feature.
If you already purchased, you can use the Register button to enter your new registration details.