Ubuntu 12.04でnmapを使用してHeartbleedの脆弱性を検索する方法は？

[root@notebook ~] lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 12.04.4 LTS
Release:    12.04
Codename:   precise
[root@notebook ~] dpkg -l nmap | grep ^ii
ii  nmap                                          5.21-1.1ubuntu1                            The Network Mapper
[root@notebook ~] wget -q https://svn.nmap.org/nmap/scripts/ssl-heartbleed.nse -O /usr/share/nmap/nselib/ssl-heartbleed.nse
[root@notebook ~] wget -q https://svn.nmap.org/nmap/nselib/tls.lua -O /usr/share/nmap/nselib/tls.lua
[root@notebook ~] wget -q https://svn.nmap.org/nmap/nselib/sslcert.lua -O /usr/share/nmap/nselib/sslcert.lua
[root@notebook ~] wget -q https://svn.nmap.org/nmap/nselib/asn1.lua -O /usr/share/nmap/nselib/asn1.lua
[root@notebook ~] wget -q https://svn.nmap.org/nmap/nselib/stdnse.lua -O /usr/share/nmap/nselib/stdnse.lua
[root@notebook ~] nmap -p 443 --script ssl-heartbleed www.ssllabs.com

Starting Nmap 5.21 ( http://nmap.org ) at 2014-06-25 07:49 CEST
NSE: failed to initialize the script engine:
/usr/share/nmap/nselib/stdnse.lua:59: attempt to index field 'socket' (a nil value)
stack traceback:
    /usr/share/nmap/nselib/stdnse.lua:59: in main chunk
    [C]: in function 'require'
    /usr/share/nmap/nse_main.lua:95: in main chunk
    [C]: ?

QUITTING!
[root@notebook ~] cat /usr/share/nmap/nselib/stdnse.lua
...
  50 --- Sleeps for a given amount of time.
  51 --
  52 -- This causes the program to yield control and not regain it until the time
  53 -- period has elapsed. The time may have a fractional part. Internally, the
  54 -- timer provides millisecond resolution.
  55 -- @name sleep
  56 -- @class function
  57 -- @param t Time to sleep, in seconds.
  58 -- @usage stdnse.sleep(1.5)
  59 _ENV.sleep = nmap.socket.sleep;
...

私の質問：何が問題なの？

nmapの前にある多くの「wget」は、nmapが以前にモジュールが欠落していると言っていたためです。