WinHTTrack, like all programs, isn’t perfect. You will inevitably run into issues as you use this program, so here are some helpful resources to help you solve problems that may arise.
http://www.httrack.com/html/faq.html -- The FAQ on the HTTrack site answers most common questions you may have about using HTTrack or WinHTTrack. Be sure to check this resource first if you have any issues.
http://danzcontrib2.free.fr/en/index.php -- This site provides hundreds of real world examples for many different issues you may run into while using HTTrack. Though unaffiliated with the HTTrack developers it has received their endorsement. You can search based on what content is missing, broken, or unfinished.
http://forum.httrack.com/ -- The official HTTrack Forums is fully searchable and includes answers to technical and usability questions that are often answered directly by the HTTrack developers. Please note that the forum is not regularly well kept, so if you wish to ask your own question it may take a while for you to receive a response.
http://www.httrack.com/html/fcguide.html -- WinHTTrack uses a GUI, but the most popular version of HTTrack uses a command line which allows for more flexibility and detail. This guide is good primer if you want to begin using this advanced version.