> My internet line is disconnecting every 1 minute
(Russia...)
> and httrack is overloading through 20-30 minutes of 
work... 

Darn.. I don't see any reliable solution to bypass the 
problem ; except maybe freezing all httrack sessions in the 
ppp ifdown callback, and unfreezing on up again? But this 
may anyway cause several errors

Example (on Debian)
/etc/ppp/ip-down.d/httrackfreeze:
for i in `ps -ef|grep httrack|grep -v grep|sed -e 's/ [ ]
*/ /g'|cut -f2 -d ' '`; do kill -STOP "$i"; done

/etc/ppp/ip-up.d/httrackunfreeze:
for i in `ps -ef|grep httrack|grep -v grep|sed -e 's/ [ ]
*/ /g'|cut -f2 -d ' '`; do kill -CONT "$i"; done