Fatal error: Call to a member function getCfg() on a non-obj

[rafaviriato]

When installing a template appears the error

Fatal error: Call to a member function getCfg() on a non-obj

the code line

<div class="sitetitle"><?php echo $mainframe->getCfg('sitename');?></div>

Does anyone know how to solve

[jcms]

you can comment that line or you this before that source code:
$mainframe = JFactory::getApplication();