I experienced same message once I tried use --catchurl. Message is misleading
in this case. 
I've diagnosed the problem via strace and found httrack is trying to resolve
my hostname but it fails.
After learning this I simply added <IP> <HOSTNAME> mapping in to /etc/hosts
and it worked.

Easy check to find out whether you suffering same problem is: 
Try ping your hostname and see if your machine can resolve it.
If not above might help.