NFS Version 4

NFS4 is not like 2 or 3. It will provide one single export as a root filesystem. So in your mount line, simply remove the path information past the first "/", which you would have supplied with NFS3. Here's are two examples:

mount -t nfs4 <address>:/ /dev/testmount
mount -t nfs4 -o rw,soft,intr 192.168.0.192:/ /temp_mnt/

Errors

The error messages that mount issues are confusing. Here's one example:

mount.nfs4: mount point /root/testmount does not exist

You will get this if you specify too much of the server-path (stop at the "/"). Weird, huh?