Two things, why not just put the code into the page instead of this line:
PHP Code:
$content = file_get_contents('http://www.generalaviationonline.com/auction/');
And secondly, you cannot use echo when spitting out something to a template. You need to assign the output to a variable and then spit out the variable in the template.
PHP Code:
$templater = vB_Template::create('navbar_auction');
$templater->register_page_templates();
$templater->register('navbar', $navbar);
$templater->register('pagetitle', $pagetitle);
$templater->register('content', $content );
print_output($templater->render());