It appears to be choking on this function:
/* override php memory limit */
$php_memory_limit = config_get_path('system/php_memory_limit', 0);
if (($php_memory_limit >= 128) && ($php_memory_limit <= get_php_max_memory())) {
ini_set("memory_limit", config_get_path('system/php_memory_limit') . "M");
}
Do you have a custom php memory size set in System > Advanced > Misc?