Root-NFS error 13

[jyhshing@cat.syr.edu (Jyh-shing)]

Hi,

I have two diskless Linux system running for a while now.
Today, I tried to add two more diskless machines .
One of them runs fine while the other one loaded the 
boot image and started up the boot process but hangs
with the following error.

Root-NFS: server returned error 13 while mounting
/tftpboot/ppptest2

What does error 13 mean ?

As far as I can tell, /etc/bootptab and /etc/exports are
setup properly and daemons restarted with kill -HUP.
I've also modified the /tftpboot/ppptest2/etc/rc.d/rc.inet1
and the corresponding HOSTNAME to the proper IP.

Where else could have caused the problem ?

Thanks in advance,

Jyh-shing Chen