Same problem here with the D525MW mainboard. I downloaded BIOS update MWPNT10N.86A v71 from 11/11/2010
My findings: the system fails to reboot without a monitor attached.
It will boot just fine, but issueing a reboot will shutdown the machine and then it hangs instead of rebooting.
I tested this with Linux, FreeBSD and Windows7. FreeBSD won't even reboot with a monitor attached and requires a manual reset.
The system will reboot with an (un-powered) screen attached, however this is weird behaviour. I hope Intel will solve this so this board can run as a headless machine.