If you've ever seen this, you've felt my pain:

# mount -vv -t nfs4 slap:/export/a/b/c /mnt
mount: pinging: prog 100003 vers 4 prot tcp port 2049
mount.nfs4: slap:/export/a/b/c failed, reason given by server: No such file or directory

My original thought was that I had a mistake in how I was exporting the file system. Come to find out, the real problem was directory permissions somewhere along /export/a/b/c. Once I at least made the directory executable, I was able to mount the filesystem without any hassle.