> I have tried running httrack without the -c option; 
> it then uses 8 simultaneous connections IIRC. I also 
> tried limiting this by specifiying 1 or 2 
> connections. It sure runs a lot slower then, but I 
> still get the errors.

What are exactly the options passed? Filters? Which 
URL? 
This may be a problem with a specific option, which 
would prevent the engine from closing a socket/file