Disclaimer, I'm a noob and just guessing but:
The first one looks like it's probing usb mass storage devices, probably an SD card reader - with no cards installed?
The acpi0 messages:
http://lists.freebsd.org/pipermail/f...ay/006503.html
The cd0: line seems to refer to an optical drive without media loaded
The da0: -da3: appears to refer to the same usb mass storage and also signifies that no media is installed.
So if the system is running normally and unless anyone tells you anything different, you can most likely ignore those warnings.