I'd like to share my experience about mirroring localhost.
I use WinXP-php 5.1-MySql 4.1-Apache2-Joomla 1.0.5 
I was getting annoying error on HTTrack saying 
Error: (404) at link localhost:8080(from primary/primary) 

actually the address localhost:8080 can be displayed by browser IE or
Firefox.

-checked MIME type, ensure that php is treated as text/html.
-tried to not follow robot.txt rules 
-choose different proxy
-choose mirror dir at the same root dir
all were not working!

I tried to save the page by browser file > save as....
cannot save! then I recognize the trouble is:
Joomla has feature to mod_rewrite Apache by .htaccess rule, basically the web
address rewritten as search engine friendly. 
turned that off and HTTrack works flawlessly.

thanks to Xavier and all for creating excellent tool.