AQTime shows this message when the installed plug-ins list contains invalid plug-ins. For instance, this happens if the list contains one or several plug-ins that refer to another plug-in, which is disabled or not installed. If you enable or disable plug-ins via the Extensions dialog, the problematic plug-ins are marked with a specific icon (
) in the dialog. To solve the problem, either remove the problematic plug-ins, or install all required plug-ins.