hidden value

i have a script that submits values to itself but when
i try to add the hidden value here...  

       print start_form,
                              "Enter a number greater than 0  ",textfield('searc
h_string'),p,
hidden(-name=>'username',-value=>'$username'),
                              submit,

                              end_form;


and print it out with

$myCGI = new CGI;
$username = $myCGI->param('username');
print "username via param is $username<br>";
$username="$ENV{REMOTE_USER}";
print "username via remote user is $username<br>";  

i get
username via param is
username via remote user is boofulls
on the first page
and
username via param is $username
username via remote user is
after i hit submit

where am i going wrong?
all i want it to do i display the hidden value that i pass!