The problem is the buttons "Next" and "Back" don't have the names expected by Advanced Installer. All you need to do it so select the two buttons, on the dialogs you are interest in, and edit their names in the right side pane. The correct names are "Back", respectively "Next". The current names, incorrect ones, are "PreviousButton" and "NextButton".
After changing the names the dialogs should be visible in the tab I mentioned previously.