while(<IN>) {
   chomp;
   my @fields = split /,/;
   my $path_str = $fields[6];
   do { warn "Empty field 7"; next } unless $path_str;
   my @path = split "\\", $path_str;
   # remove null fields if you really have \\ in there
   @path = grep { $_ } @path;
   # assuming you want to remove the 17 and 16 dirs in the example
   my $fixed_path = join "\\", @path[0,2,3]
   my $out = join '|', @fields[0..5], $fixed_path, "\n";
   print OUT $out;
}