PHP Error: panels.module, line 292

Following installation of the panels module, pages accessing the module appear blank. Apache error_log reports:

PHP Fatal error: Only variables can be referenced in /.../modules/panels/panels.module on line 292

Line 292 reads:

$default_radio = array_shift(array_keys($layout['content areas']));

Recommended patch:

$default_radio = array_keys($layout['content areas']);
$default_radio = array_shift($default_radio);