...The Config file is opened by some other resource.

I get the above error when I add or modify and NFS Export. This just
recently started happening. Also, if a unix client unmounts one of the
exports and then remounts it, it will get a permission denied error. Any
new mounts will also get a permission denied error. A reboot fixed the
problem last time but this has been working fine until recently. No changes
have been made to the server either. Any ideas?