[CentOS] autofs problems

We have about 800 CentOS 5.2 servers and our university. We use NFS
being served from over 10 NetApp frames. We use autofs for to mount up
our partitions. There have been times where we can't cd into the
directory. It says the directory does not exist. On some servers it
works but on others it does not. Typically we restart amd and autofs
to resolve this issue. But sometimes it does not even work. A reboot
fixes the problem. I am wondering if anyone knows any tricks to check
if autofs is working properly on the system and also what I should do
in a situation like this.

TIA