> It is not an obscure bug, these problems are
> repeatedly reported since years. 

But very hard to reproduce ; this errors means that httrack emited a "continue
to download this file" request (which is unusual - the download might have
been aborted suddenly), but the file could not be found anymore when the
response appeared.

Some bugs remains during months or years because they are really hard to
reproduce, not because of lack of interest. The internal httrack engine code
is quite complex (and not really clean I admit), and fixing low-level bugs is
a tough job.

If you have a clearly reproductible case, do not hesitate to describe it.