If httrack doesn't download the files of the left menu
(option Spider/Parse java files and Links/Attempt to detect
all links... ticked), you have the list of addresses  (or
scan rules) in this file :
<http://web.compranet.gob.mx/treemenu.html>
If the problem lies with the java applet, have a look in
MSIE cache and copy the missing .class files in your mirror
in the right folders, then remove the figure between brackets.
This should allow you to browse offline.