when you updated to 1.2 I believe it updates the default kernel, there are some newer ones you can download them from the fog configuration tab, there is an option for downloading kernels.
downloading an additional PXE boot image, save it as a custom option bzimage###. then go to your system inventory and set the machine to use a custom boot loader, fog/kernel/bzimage###. Then make sure that you delete the pending task, so that it picks up the custom kernel when it creates the new task. Since your other systems are working fine with the current default it would be best to test a different kernel without overwriting the current one.
you can look here [url]http://www.fogproject.org/wiki/index.php/WorkingDevices[/url] to see if your system is on the list and what kernels have been tested to work with it.