Strange NFS root booting behavior.

I've set up a dhcp server to support two (or more) clients, which mount 
their root on
an nfs shared volume.

For one client, the booting process has one symptom:

after the initial PXEBOOT and getting the parameters from the dhcp 
server, the
boot process hangs at:

pxe_boot: gateway ip: ...

And after a few minutes eventuall loads the loader.conf

and after a few more minutes, loads the kernel, which seems pretty speedy
given the twirlers.

On the other system, oddly, the boot process seems to whip through the
above boot section with no hesitation. However, after the kernel is
loaded, and the init starts up, with in a ver few initial commands there
is a diagnostic to the effect:

Starting file system checks:

Then ...

mount /: Bad file descriptor
Mounting root filesystem rw failed, startup aborted.

Since I'm booting off of the same hierarchy, I did create a ramdisk and 
initialized
a file system to have '/var/run' created local to the client systems.

Are there other things that need to be separated for each client? And would
failing to do set these up, give the above behavior, in particular the 
failure to boot
and run through the normal rc scripts.

Thanks
John Clark.