Startup Error

Unexpected Exception:
"/usr/local/www/topics.info.com/releases/20120117135950/logs/php_error.log" cannot be opened with mode "a"

#0 /usr/local/www/topics.info.com/releases/20120117135950/app/controllers/ErrorController.php(57): Zend_Log_Writer_Stream->__construct('/usr/local/www/...')
#1 /usr/local/www/topics.info.com/releases/20120117135950/app/controllers/ErrorController.php(18): ErrorController->_log()
#2 /usr/local/www/php_libs/Zend/1.9.8/Zend/Controller/Action.php(133): ErrorController->init()
#3 /usr/local/www/php_libs/Zend/1.9.8/Zend/Controller/Dispatcher/Standard.php(262): Zend_Controller_Action->__construct(Object(Zend_Controller_Request_Http), Object(Zend_Controller_Response_Http), Array)
#4 /usr/local/www/php_libs/Zend/1.9.8/Zend/Controller/Front.php(946): Zend_Controller_Dispatcher_Standard->dispatch(Object(Zend_Controller_Request_Http), Object(Zend_Controller_Response_Http))
#5 /usr/local/www/topics.info.com/releases/20120117135950/app/Bootstrap.php(37): Zend_Controller_Front->dispatch()
#6 /usr/local/www/topics.info.com/releases/20120117135950/www/index.php(3): Bootstrap::run()
#7 {main}