JSI Tip 4563. Your computers ACPI BIOS Is attempting to write to an illegal IO port address (0x80, 0x400, 0xcf8, 0xcfc) while running Windows XP?

Microsoft Knowledge Base Article 283649 Explains that you may find an "ACPI BIOS is attempting to write to an illegal IO port address" error message in the event viewer’s system event log. This behavior occurs when BIOS tries to access ports by using an AML, endangering system.