php call to plugin breaking site

i’m using a php line in the header.php file (ie: <?php putRevSlider(“slider1”, “homepage”) ?>) which calls to a plugin, and if that plugin is not activated then nothing on the site loads. this is true of another plugin as well. i can foresee a case where something is out of date and the plugin doesn’t load even though it’s activated, and am wondering if there’s code that’s specific to twentytwelve that would enable to site to load even if a plugin isn’t working?

i believe i’ve used such php lines in other themes without the plugin activated and it hasn’t broken the site, so i’m wondering if there’s something specific here to twentytwelve.

thanks!