Windows may display a 2727 installer error or restart pending message when you upgrade from Boot Camp 2.2 on a Mac running Mac OS X 10.5 (Leopard) to Boot Camp 3.0 on a Mac running Mac OS X 10.6 (Snow Leopard).
Source:Boot Camp: 2727 error or restart pending message when upgrading Boot Camp 2.2 to 3.0
