ikegami:

"The process() method then returns 1 to indicate success", which you proceed to print. Don't print it if you don't want to see it.

Just to be perfectly clear, the statement printing return value of  process() method:
    print $tt->process('page.tt', $vars) || die $tt->error();
A statement not printing return value of  process() method:
    $tt->process('page.tt', $vars) || die $tt->error();