I don't know about the directory-structure of Mint. There should be a directory /etc/init.d or /etc/rc.d where the daemons reside which are started by the startscripts. Look which name the daemon has in your distribution, nfsd or rc.nfsd. then execute
Code:
/etc/init.d/nfsd restart
or whatever the correct path for the daemon on your system is.
Be sure to configure nfsd to start while systemstart.
Markus