NFS mount error

[Geoffrey Leach]

I've got a simple network, systems 'A' and 'B' connected via wireless. 
B wants to mount A's /, /home and /usr/local. The fstab entries are
A:/               /A                nfs	defaults	0 0
A:/home           /A-home           nfs	defaults	0 0
A:/usr/local      /A-ul             nfs	defaults	0 0

With this, B should do the mounts at boot time, assuming A is on line, 
which it is.

The curious thing is that the mount of A:/ works fine. mounts of A:/
home and A:/usr/local fail with "mount.nfs: Unknown error 521"

FWIW, B is running Fedora 10, while A is running up-to-date Fedora 12.
This worked find prior to reloading F12 on A. Presumably I've missed 
something -- any ideas?

Thanks.