If you don't post code for something like this it means you think there is something wrong with perl, and not with what you are doing :).

Strip down your script to just the open statement and look at it again. If you still can't see what's wrong, then post the code so we can all see it.

In the meantime the following works for me (no added whitespace):

#!/usr/bin/perl -w
use strict;
use CGI ':standard';



open FH, '> data.txt' or die $!;

print FH 'testing123';

close FH;


print header(), start_html(-title => "test");

print "finished";

print end_html();
[download]

Hope that helps...