The other thing to verify is that the portmapper is running. You can check this by running rcportmap status.
rcportmap status: Checking for RPC portmap daemon: running
If it is running, then run rpcinfo -p and see if nfs is listed in the output. NFS relies on RPC and if the RPC services are not running properly it will fail.
rpcinfo -p: program vers proto port 100000 2 tcp 111 portmapper 100000 2 udp 111 portmapper 100003 2 udp 2049 nfs 100003 3 udp 2049 nfs 100021 1 udp 32831 nlockmgr 100021 3 udp 32831 nlockmgr 100021 4 udp 32831 nlockmgr 100005 1 udp 32832 mountd 100005 1 tcp 33909 mountd 100005 2 udp 32832 mountd 100005 2 tcp 33909 mountd 100005 3 udp 32832 mountd 100005 3 tcp 33909 mountd 100024 1 udp 32834 status 100024 1 tcp 33910 status P_s