Mac won't sleep when XAMPP Control Panel is Active

[steelbit]

I don't remember this happening before the Leopard 10.5.2 update, but I've noticed that if my XAMPP Control Panel is running, my MacBook will not go to sleep. Does anyone know why that is, and if it is related to the Leopard update?

I'm pretty new to the Mac world, so I would like to understand what's going on.