If the Network.prefPane folder is empty, then it was probably deleted. Maybe accidentally, but since it's gone there is no way to reinstate it without reinstalling OS X. Boot to your Recovery Partition (hold down command + r and reboot). Once in Recovery, reinstall Mountain Lion. The reinstall will not remove your data, documents, music, movies, etc, but it will overwrite system files and kexts. Just in case.... make a backup first with Time Machine before reinstalling Mountain Lion.