> i have already copied my websites in windows and i
> have .whtt files and in linux it won't update them.
> It just asks for url to download and doesn't give
> browser option fetch an existing .whtt. can someone

whtt files are zero length, they contain no information.
Under windows clicking on one opens winhttrack to the corresponding mirror.

Have you started webhttrack, set the Base path (page with Project name pull
down)