> But, the crash still remains, tough httrack
> continues. It reports something like:
> PANIC! : Crash adding error, unexpected error
> found.. [4250]

Bug found: the engine was in troubles when links were put in background.

Thanks for the report! Here's the fix for 3.39.7:

--- htsparse.c.orig     2005-09-01 19:39:12.506784218 +0200
+++ htsparse.c  2005-09-01 19:39:26.242573819 +0200
@@ -4245,7 +4245,7 @@
       /* Add in backing (back_index() will respond correctly) */
       if
(back_add_if_not_exists(sback,opt,cache,adr,fil,save,NULL,NULL,0,NULL) != -1)
{
         int b;
-        b=back_index(sback,adr,fil,0);
+        b=back_index(sback,adr,fil,save);
         if (b<0) {
           printf("PANIC! : Crash adding error, unexpected error found..
[%d]\n",__LINE__);
           XH_uninit;    // désallocation mémoire & buffers
@@ -4291,7 +4291,7 @@

           /* Re-Add wiht correct type */
           if
(back_add_if_not_exists(sback,opt,cache,adr,fil,save,NULL,NULL,0,NULL) != -1)
{
-            b=back_index(sback,adr,fil,0);
+            b=back_index(sback,adr,fil,save);
           }
           if (b<0) {
             printf("PANIC! : Crash adding error, unexpected error found..
[%d]\n",__LINE__);