In

Zend_Log::_constructWriterFromConfig($config);

on line 135, the variable {{$writerName}} is undefined and on line 132 parentheses are missing.

if (!$writer instanceof Zend_Log_Writer_Abstract) {
    /** @see Zend_Log_Exception */
    require_once 'Zend/Log/Exception.php';
    throw new Zend_Log_Exception("{$writerName} does not extend Zend_Log_Writer_Abstract!");
}

A fix could be (use of double quotation marks is discouraged, by the way):

if (!($writer instanceof Zend_Log_Writer_Abstract)) {
    /** @see Zend_Log_Exception */
    require_once 'Zend/Log/Exception.php';
    $writerName = is_object($writer)
                ? get_class($writer)
                : 'The specified writer'
    ;
    throw new Zend_Log_Exception($writerName . 'does not extend Zend_Log_Writer_Abstract!');
}