use warnings;
use strict;
use CGI;
use Proc::Background;

my $args = new CGI;

if(!defined $args->param('step'))
{
  print $args->header;
  blah blah blah
  print $args->end_html;
  exit;
}
if($args->param('step') == 0)
{
  $step = 1;
  my $proc1 = Proc::Background->new("perl","./myscript.pl","arg1","arg2");
}
elsif($args->param('step') > 0)
{
  $step = $args->param('step');
  $step ++;
}
print $args->header(-Refresh=>"5;url=http://localhost/cgi-bin/mycgi.pl?step=$step");
...
print <input type=\"hidden\" name=\"step\" value=\"$step\">";
print $args->end_html;
exit;