IE does not like cache pragmas very much... more information here and here

Instead you can approach in this way:

1) instead of a static html form, generate it with Perl
2) in place of the simple name of your script (to put in the "action" attribute of the form) put the name followed by a ? and a random number.

So, IE will think that you're calling a different script.

For example:

my $rand_num=rand time;
$rand_num*=10000;

my $cgi='mycgi.pl?'.$rand_num;
[download]

Kudos to larsen for showing me this trick