build.c line around line 5026 in do_mpedit find

   if( !str_cmp( arg2, "delete" ) )
   {
      int num;
      bool found;

      if( !mprog )
      {
         send_to_char( "That mobile has no mob programs.\r\n", ch );
         return;
      }
      argument = one_argument( argument, arg4 );
      if( value < 1 )
      {
         send_to_char( "Program not found.\r\n", ch );
         return;
      }
      cnt = 0;
      found = false;
      for( mprg = mprog; mprg; mprg = mprg->next )
      {
         if( ++cnt == value )
         {
            mptype = mprg->type;
            found = true;
            break;
         }
      }
      if( !found )
      {
         send_to_char( "Program not found.\r\n", ch );
         return;
      }
      cnt = num = 0;
      for( mprg = mprog; mprg; mprg = mprg->next )
         if( mprg->type == mptype )
            num++;
      if( value == 1 )
      {
         mprg_next = victim->pIndexData->first_mudprogs;
         victim->pIndexData->first_mudprogs = mprg_next->next;
         victim->pIndexData->first_mudprogs->prev = NULL; /* That's this line */
      }
      else
         for( mprg = mprog; mprg; mprg = mprg_next )
         {
            mprg_next = mprg->next;
            if( ++cnt == ( value - 1 ) )
            {
               mprg->next = mprg_next->next;
               if( mprg->next )
                  mprg->next->prev = mprg;
               break;
            }
         }
      if( mprg_next )
      {
         STRFREE( mprg_next->arglist );
         STRFREE( mprg_next->comlist );
         mprg_next->next = NULL;
         mprg_next->prev = NULL;
         DISPOSE( mprg_next );
         if( num <= 1 )
            xREMOVE_BIT( victim->pIndexData->progtypes, mptype );
         send_to_char( "Program removed.\r\n", ch );
      }
      return;
   }

change it to this

   if( !str_cmp( arg2, "delete" ) )
   {
      int num;
      bool found;

      if( !mprog )
      {
         send_to_char( "That mobile has no mob programs.\r\n", ch );
         return;
      }
      argument = one_argument( argument, arg4 );
      if( value < 1 )
      {
         send_to_char( "Program not found.\r\n", ch );
         return;
      }
      cnt = 0;
      found = false;
      for( mprg = mprog; mprg; mprg = mprg->next )
      {
         if( ++cnt == value )
         {
            mptype = mprg->type;
            found = true;
            break;
         }
      }
      if( !found )
      {
         send_to_char( "Program not found.\r\n", ch );
         return;
      }
      cnt = num = 0;
      for( mprg = mprog; mprg; mprg = mprg->next )
         if( mprg->type == mptype )
            num++;
      if( value == 1 )
      {
         mprg_next = victim->pIndexData->first_mudprogs;
         victim->pIndexData->first_mudprogs = mprg_next->next;
         if( victim->pIndexData->first_mudprogs ) /* Checking here helps keep it from crashing */
            victim->pIndexData->first_mudprogs->prev = NULL;
      }
      else
         for( mprg = mprog; mprg; mprg = mprg_next )
         {
            mprg_next = mprg->next;
            if( ++cnt == ( value - 1 ) )
            {
               mprg->next = mprg_next->next;
               if( mprg->next )
                  mprg->next->prev = mprg;
               break;
            }
         }
      if( mprg_next )
      {
         STRFREE( mprg_next->arglist );
         STRFREE( mprg_next->comlist );
         mprg_next->next = NULL;
         mprg_next->prev = NULL;
         DISPOSE( mprg_next );
         if( num <= 1 )
            xREMOVE_BIT( victim->pIndexData->progtypes, mptype );
         send_to_char( "Program removed.\r\n", ch );
      }
      return;
   }