I don't know what the problem might be. One possibility is that Netscape's server is more aggressive about killing CGI programs when they don't produce valid headers. Try this at the very start of your program:

BEGIN {
  print "Content-Type: text/plain\n\n";
  open(STDERR, ">&STDOUT");
}
[download]

That will let you see all that is printed by your program. Perhaps it's not producing a valid header? Maybe something odd is coming from CGI.pm.

Does the Netscape server have an option to disable cookies or anything like that? It might be filtering outgoing headers. Beyond that, I really haven't a clue. I'd love to find out when you solve it, though.

Good luck!

Nat