[texworks] I cannot enable plugin scripting languages

[Antonio Majer]

Hi all. 
I apologize for the following newbie question.
I’d like to use lua for my scripts, but unfortunately the checkbox under “Scripts” in my Preferences dialog form is not activated.
Have a look here if you like:
http://i1074.photobucket.com/albums/w419/antmjr/texworks_zps9q25v2ex.jpg
Can someone give me a suggestion on how to solve this problem?
It seems there is something (antivirus, firewall, etc.) preventing a plugin to be installed. Or is it missed? have I to download it from somewhare?
I have Windows 7 and Norton Antivirus installed.
Antonio


----- configuration info -----
TeXworks version : 0.4.6r.c29723a (MiKTeX 2.9 64-bit)
Install location : C:/Program Files/MiKTeX 2.9/miktex/bin/x64/miktex-texworks.exe
Library path     : C:/Users/Admin/AppData/Local/MiKTeX/2.9/TeXworks/0.4\
pdfTeX location  : C:/Program Files/MiKTeX 2.9/miktex/bin/x64/pdftex.exe
Operating system : Windows 7 Professional, 64-bit, Service Pack 1, build 7601
Qt version      : 5.4.1 (build) / 5.4.1 (runtime)
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