>   I mirrored my site (www.htsol.com) and the main menu gif
> items were renamed or missing, for example:  
supportmenu_b1.gif.

The javascript is way too complex for httrack:
mainMenuItem
("mainmenu_b1",".gif",36,76,http://www.htsol.com","","",2,2
,"mainmenu_plain");

The function "mainMenuItem" is joining the two arguments 
("mainmenu_b1" and ".gif" to form the final filename -- 
this is not understood by httrack.

Such syntax would be understood:
mainMenuItem("mainmenu_b1.gif",36,36...)

because httrack will then "recognize" the filename inside 
the parameter list.