use... bla bla just as above :)
my $EmailAddress = $cgi->param('EmailAddress');

if($EmailAddress) {
        my $res = Mail::CheckUser::check_email($EmailAddress);
           if($res==1) {
               print "E-mail address $EmailAddress is OK\n";
           } else {
               print "E-mail address $EmailAddress isn't valid: ",
        }
}