> 
> > Mirror www.aiki-viet.com.vn NOT aiki-viet.com.vn
>
> I thought they are the same.
>

To an online browser, they pretty much *are* the same.  However, HTT will ONLY
get what you tell it to get.  And if there are links ("absolute" links) from a
page on <http://aiki-viet.com.vn/> to <http://www.aiki-viet.com.vn/>, then with
default settings, HTT will not download the files on the 'www' host.

The converse is true too.   If there are absolute (non-relative) links from a
page on <http://www.aiki-viet.com.vn/> to <http://aiki-viet.com.vn/>, with default
settings HTT will not download the files on the non-'www' host.

In WinHTT, if you go into Set Options and look at the Experts Only tab, the
default "Global Travel Mode" is "Stay on the same address".  www.xx.yy is a
different address than, say, ftp.xx.yy as well as (blank.)xx.yy.  You can
change to "Stay on the same domain" or you can add +*.xx.yy to your scan
filters.

In your situation, putting 
<http://aiki-viet.com.vn/>
<http://www.aiki-viet.com.vn/>
both URL's as the starting URL's should have done the same thing.  (But
better?)  However, if the site is coded with relative links instead of
absolute, then either one would have worked the same.

HTH,
~b